U.S. patent application number 11/755587 was filed with the patent office on 2008-12-04 for voiding event identification based on patient input.
This patent application is currently assigned to Medtronic, Inc.. Invention is credited to Martin T. Gerber, John C. Rondoni.
Application Number | 20080300651 11/755587 |
Document ID | / |
Family ID | 39598425 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080300651 |
Kind Code |
A1 |
Gerber; Martin T. ; et
al. |
December 4, 2008 |
VOIDING EVENT IDENTIFICATION BASED ON PATIENT INPUT
Abstract
An implantable medical device (IMD) is configured to operate as
an automatic voiding diary for logging urinary and/or fecal voiding
events. The IMD detects urinary and/or fecal voiding events and
generates data that identifies detected events as voluntary or
involuntary events. In particular, the IMD generates the
identification data based on a patient defined action. In one
embodiment, the patient defined action is the patient tapping on
the skin located above the IMD. The IMD may generate the
identification data based on one or more characteristics of the
tapping, e.g., the number, frequency, duration, or pattern of taps.
The IMD may also generate the identification data based on a lack
of input during a specific range of time after a detected voiding
event. In some embodiments, the identification data may be used to
identify a false positive, i.e., an event that was incorrectly
detected by the IMD.
Inventors: |
Gerber; Martin T.; (Maple
Grove, MN) ; Rondoni; John C.; (Plymouth,
MN) |
Correspondence
Address: |
SHUMAKER & SIEFFERT, P. A.
1625 RADIO DRIVE, SUITE 300
WOODBURY
MN
55125
US
|
Assignee: |
Medtronic, Inc.
Minneapolis
MN
|
Family ID: |
39598425 |
Appl. No.: |
11/755587 |
Filed: |
May 30, 2007 |
Current U.S.
Class: |
607/41 |
Current CPC
Class: |
A61B 5/205 20130101;
A61N 1/37217 20130101; A61N 1/05 20130101; A61B 5/204 20130101;
A61N 1/36007 20130101; A61B 5/202 20130101; A61N 1/0558 20130101;
A61B 5/0031 20130101 |
Class at
Publication: |
607/41 |
International
Class: |
A61N 1/36 20060101
A61N001/36 |
Claims
1. A method comprising: receiving a sensor signal that varies as a
function of a parameter associated with a voiding event of a
patient; determining whether the voiding event occurred based on
the sensor signal; receiving input from the patient, wherein the
input comprises a patient defined action that is received via a
device implanted within the patient; and associating the input with
an occurrence of the voiding event.
2. The method of claim 1, wherein the device is implanted within
subcutaneous tissue of the patient, and wherein receiving input
from the patient comprises receiving one or more taps through the
skin of the patient proximate to the device.
3. The method of claim 1, wherein the parameter associated with the
voiding event comprises at least one of nerve activity, bladder
volume, bladder pressure, bladder impedance, sphincter pressure,
bowel pressure, motion of a portion of an intestine, motion of a
sigmoid colon, motion of a rectum or a sound associated with the
voiding event.
4. The method of claim 1, further comprising determining whether
the voiding event was a controlled event or an involuntary event
based on the input associated with the voiding event.
5. The method of claim 4, wherein the device is implanted within
subcutaneous tissue of the patient, and wherein the patient defined
action comprises one or more taps on the skin of the patient
proximate to the device, and wherein determining whether the
voiding event was a controlled event or an involuntary event based
on the input associated with the voiding event comprises
determining a characteristic of the tapping, and the characteristic
comprising at least one of a number, frequency, pattern or duration
of the tapping.
6. The method of claim 4, further comprising generating
identification data that indicates whether the voiding event was
the controlled event or the involuntary event and storing the
identification data in a memory.
7. The method of claim 6, wherein storing the identification data
in the memory comprises transmitting the identification data to an
external device via wireless telemetry, wherein the external device
comprises the memory.
8. The method of claim 7, further comprising presenting the
identification data to a user via a display of the external
device.
9. The method of claim 6, wherein generating the identification
data comprises generating an indicator that identifies the voiding
event associated with the input as a false positive.
10. The method of claim 9, wherein generating the indicator that
identifies the voiding event as the false positive comprises
generating the data that identifies the voiding event associated
with the input as the false positive when the input is not received
within a pre-determined time after the voiding event is
detected.
11. The method of claim 4, further comprising adjusting one or more
therapy parameters based on the determination of whether the
voiding event was the controlled event or the involuntary
event.
12. The method of claim 11, wherein the therapy parameters
comprises at least one of a voltage or current amplitude of
electrical stimulation, pulse width of electrical stimulation,
pulse frequency of electrical stimulation, a drug dosage, or a
frequency of a delivery of a drug.
13. The method of claim 4, further comprising controlling the
delivery of therapy to the patient based on the determination of
whether the voiding event was the controlled event or the
involuntary event.
14. The method of claim 13, wherein delivering therapy to the
patient comprises delivering electrical stimulation to the patient
or delivering a fluid to the patient.
15. The method of claim 1, wherein the method further comprising
delivering therapy to the patient and evaluating efficacy of the
therapy based on the identification data.
16. The method of claim 1, further comprising receiving
confirmation from the patient that the determination of whether the
voiding event was the controlled event or the involuntary event is
valid or invalid.
17. The method of claim 1, wherein the signal comprises a first
signal and the device comprises an accelerometer, wherein receiving
the input comprises detecting a movement of the device via a second
signal generated by at least one of the accelerometer or a
microphone.
18. The method of claim 1, wherein determining whether the voiding
event occurred based on the sensor signal comprises comparing a
sample of the sensor signal to a signal template.
19. The method of claim 18, further comprising generating an
example sensor signal during an actual voiding event, wherein the
signal template is defined based on one or more characteristics of
a portion of the example sensor signal.
20. The method of claim 1, wherein receiving the input from the
patient comprises receiving the input within a pre-determined
period of time following the determination that the voiding event
occurred.
21. A system comprising: a sensor that generates an electrical
signal that varies as function of a parameter associated with a
voiding event of a patient; a processor that processes the
electrical signal to detect the voiding event; and an implantable
input mechanism configured to receive an input from the patient,
the input comprising a patient defined action, wherein the
processor associates the input with the detected voiding event.
22. The system of claim 21, wherein the patient defined action
comprises a tapping action by the patient at a location proximate
to an implant site for the implantable medical device.
23. The system of claim 21, wherein the parameter comprises at
least one of nerve activity, bladder volume, bladder pressure,
bladder impedance, sphincter pressure, bowel pressure, motion of a
portion of an intestine, motion of a sigmoid colon, motion of a
rectum or a sound associated with the voiding event.
24. The system of claim 21, wherein the processor determines
whether the detected voiding event was a controlled event or an
involuntary event based on the patient defined action.
25. The system of claim 24, wherein the patient defined action
comprises a tapping action by the patient at a location proximate
to an implant site for the implantable medical device, and wherein
the processor determines whether the detected voiding event was the
controlled event or the involuntary event based on one or more
characteristics of the tapping action, the characteristics
comprising at least one of number, a frequency, a pattern or a
duration of the tapping action.
26. The system of claim 24, further comprising a memory, wherein
the processor generates identification data that indicates whether
the voiding event was the controlled event or the involuntary event
and stores the identification data in the memory.
27. The system of claim 26, further comprising a medical device
programmer comprising the memory.
28. The system of claim 26, wherein processor generates the
identification data if the input mechanism receives the input
within a predetermined period of time following the detected
voiding event.
29. The system of claim 26, wherein the identification data
identifies the detected voiding event as a false positive based on
the input.
30. The system of claim 29, wherein the processor generates
identification data that identifies the detected voiding event as
the false positive when the input mechanism does not receive the
input within a pre-determined period of time following the detected
voiding event.
31. The system of claim 21, wherein the input mechanism comprises
at least one of a single-axis accelerometer or a multiple-axis
accelerometer, and wherein the patient defined action results in a
movement of the input mechanism.
32. The system of claim 21, further comprising a therapy delivery
module and one or more therapy elements coupled to the therapy
delivery module to deliver therapy to the patient, wherein the
therapy comprises at least one of electrical stimulation or drug
therapy.
33. The system of claim 21, wherein the sensor, the processor, and
the implantable input mechanism are enclosed in a common
housing.
34. The system of claim 21, wherein the input mechanism comprises a
microphone.
35. A computer-readable medium comprising instructions that cause a
processor to: receive a sensor signal that varies as a function of
a parameter associated with a voiding event of a patient; determine
whether the voiding event occurred based on the sensor signal;
receive input from the patient via a patient defined action that is
received via a device implanted within the patient; and determine
whether the voiding event was a controlled event or an involuntary
event based on the input.
Description
TECHNICAL FIELD
[0001] The invention relates to medical devices and, more
particularly, devices for the treatment or diagnosis of urinary or
fecal incontinence.
BACKGROUND
[0002] Urinary incontinence, or an inability to control urinary
function, is a common problem afflicting people of all ages,
genders, and races. Various muscles, nerves, organs and conduits
within the urinary tract cooperate to collect, store and release
urine. A variety of disorders may compromise urinary tract
performance and contribute to incontinence. Many of the disorders
may be associated with aging, injury or illness.
[0003] In some cases, urinary incontinence can be attributed to
improper sphincter function, either in the internal urinary
sphincter or external urinary sphincter. For example, aging can
often result in weakened sphincter muscles, which causes
incontinence. Some patients also may suffer from nerve disorders
that prevent proper triggering and operation of the bladder or
sphincter muscles. Nerves running though the pelvic floor stimulate
contractility in the sphincter. A breakdown in communication
between the nervous system and the urinary sphincter can result in
urinary incontinence.
[0004] Monitoring urinary incontinence aids a clinician in
diagnosing the precise condition of the patient. For example, a
clinician may monitor parameters of voiding events, such as time of
voiding events (voluntary and involuntary), volume of leaked fluid
for an event, number of voiding events, and contents of urine, in
order to diagnose the condition of the patient. Accordingly,
monitoring may include collecting urine samples from the patient
and/or maintaining a patient voiding diary in which the patient
logs voluntary voiding events, involuntary voiding events, i.e.,
leakage, or other related problems. The patient may keep the
voiding diary on paper or in an electronic device. The clinician
may review the samples to determine the contents of the urine and
may review the diary to view the frequency and number of voiding
events experienced by the patient. In some cases, the clinician may
tailor a therapy, such as electrical stimulation, according to the
diary and the contents of the urine samples.
SUMMARY
[0005] This disclosure describes methods and systems for
maintaining an automatic voiding diary. The device detects urinary
or fecal voiding events by processing a signal generated by a
sensor and records voiding information for the detected voiding
events. The voiding information is wirelessly transmitted to an
external device, such as a patient or clinician programmer, that
presents the voiding information to an authorized user, such as a
clinician. The voiding information obtained over a series of
voiding events forms an automated voiding diary that is useful for
diagnosing a condition of the patient and determining the efficacy
of therapy delivered to treat urinary or fecal incontinence. A
clinician may also manually adjust therapy parameters based on the
voiding information. In some embodiments, the device may include
therapy elements or communicate with a therapy delivery device to
deliver therapy, e.g., electrical stimulation, drug therapy, or a
combination of both, or automatically adjust therapy parameters
based on the voiding information.
[0006] Maintaining an accurate voiding diary is often difficult for
a patient. With some manually-maintained voiding diaries, the
patient manually tracks voiding event, such as by manually writing
down the date and time of the voiding event or providing an input
via an electronic device. With manual voiding diaries, there may be
a risk that the patient may neglect or forget to record all the
necessary information. For example, a patient may neglect or forget
to record the time at which the voiding event occurred or identify
the voiding event as a voluntary or involuntary event. A manual
diary can also be inaccurate because entries by the patient are
subjective and may be influenced by embarrassment or other
issues.
[0007] This disclosure describes various systems and methods that
provide an automatic voiding diary that records a patient's voiding
events without the need for significant patient interaction. In one
embodiment, the automatic voiding diary detects voiding events
based on an electrical signal generated by a microphone. The
microphone may be a crystal microphone, condenser microphone, a
ribbon microphone, or other type of microphone. The microphone
translates sounds associated with voiding events into an electrical
signal. The sounds may be internal sounds of the patient or
external sounds. Internal sounds may be sounds generated by the
bladder, urinary tract, rectum, intestines, or other organs and
tissue that produce noise indicative of a urinary or fecal voiding
event. External sounds may include sounds produced by the patient
or environment during a voiding event, such as fluid being voided
into a toilet, flushing of a toilet, fluid exiting an opening in
the urethra of the patient, or other sound associated with voiding
events.
[0008] Detecting voiding events based on the electrical signal
generated by the microphone may involve processing the signal by,
for example, comparing or correlating the electrical signal with a
voiding signature stored in memory. The voiding signature includes
a characteristic of an electrical signal that is generated during
an actual voiding event for a patient. In one embodiment, the
voiding signature used to detect voiding events is an example
signal generated by the microphone during an actual voiding event.
The voiding signature may be individualized to a particular patient
or may be applicable to more than one patient. This example signal
is referred to as a signal template. In this way, the automatic
voiding diary may utilize an initial training or calibration mode
to establish a voiding signature, i.e., capture a signal template,
that can be used to detect a voiding signature in the signal
generated by the microphone.
[0009] The automatic voiding diary may be configured as an
implantable medical device (IMD) or an external device. When
implemented as an IMD, the microphone may be located on or within a
housing of the IMD or on a lead coupled to an IMD. In one example
embodiment, the IMD may be configured as an independent diagnostic
device that wirelessly communicates with an implantable therapy
delivery device, such as an implantable neurostimulator (INS) or
implantable drug pump, and external programmers for the implantable
therapy delivery device. In another example embodiment, the
automatic voiding diary may be configured as an IMD that operates
as an automatic voiding diary and a therapy delivery device.
[0010] When implemented as an external device, the automatic
voiding diary may be implemented as part of a personal digital
assistant (PDA), cell phone, watch, programmer for an INS or other
implantable therapy delivery device, or other personal electronic
device. Alternatively, the automatic voiding diary may be
implemented as a dedicated device that the patient may carry or
attach to clothing. In any case, the automatic voiding diary may be
configured to communicate with a implantable therapy delivery
device and programmers for the implantable therapy delivery
device.
[0011] In some embodiments, a device may include a feature for
identifying detected voiding events as voluntary or involuntary
events based on a patient defined action. The user friendly feature
is useful for maintaining a substantially automatic voiding diary
implanted in the patient to identify an automatically detected
voiding event based on a patient defined action. For example, the
patient defined action may include manually tapping the skin
located proximate to the automatic voiding diary. In this example,
the automatic voiding diary includes an accelerometer that
generates an electrical signal based on one or more characteristics
of the tapping, e.g., the number, frequency, and duration. The
automatic voiding diary processes the accelerometer signal and
records the appropriate identification information in memory.
[0012] In some embodiments, the lack of a patient defined action
may be used to provide additional information. For example, an
automatically detected voiding event may be identified as a false
positive when a patient defined action is not received within a
pre-determined period of time following the detection of the event.
Identifying voiding events based on a patient defined action that
is detected via an implanted medical device may eliminate the need
for the patient to carry a separate external programmer to enter
identification information for detected voiding events. The
identification information in the voiding diary may be particularly
useful to a clinician for determining the efficacy of therapy and
manually adjusting therapy parameters. In one embodiment, a therapy
delivery device automatically adjust therapy parameters or deliver
therapy to prevent or reduce involuntary voiding events in the
future in response to the automatic voiding diary receiving input,
i.e., a patient defined action, that identifies a voiding event as
an involuntary event.
[0013] In another example embodiment, an implantable medical lead
that carries one or more sensors is coupled to the automatic
voiding diary or, more specifically, a device that includes the
automatic voiding diary. The elongated body of the medical lead
extends between a proximal end coupled to the automatic voiding
diary device and a distal end that carries the one or more sensors.
The automatic voiding diary device processes the signals generated
by the sensors to detect voiding events. The sensors may be one or
more microphones, pressure sensors, flow sensors, strain gauges,
sensing electrodes, temperature sensors, or any other type of
sensor used for sensing a parameter associated with voiding
events.
[0014] The lead may be particularly advantageous in embodiments
that use the automatic voiding diary device in combination with a
therapy delivery device. In such embodiments, the lead may be
introduced to a target sensing site in the same way as a therapy
lead is introduced to a target therapy site. In other words,
although the target sensing and stimulation sites may be at
different locations, the leads can be introduced through a single
incision. For example, a target therapy site may be proximate to a
sacral nerve, such as the S3 sacral nerve. Typically, a therapy
lead, i.e., a lead carrying stimulation electrodes or a fluid
delivery device that delivers one or more drugs, is introduced into
the S3 sacral foramen to access the sacral nerve. Stimulation of
the S3 sacral nerve may help treat urinary and fecal control
disorders. In this case, the sensing lead described in this
disclosure is introduced through the same or a different foramen
and positioned or guided to the target sensing site. In this way,
additional trauma to the patient attributable to the implantation
of the sensing lead is avoided.
[0015] Further, some embodiments may utilize a combination lead. A
combination lead carries sensors for detecting voiding events
proximate to its distal end and delivers therapy for urinary or
fecal incontinence. One example of a combination lead is a medical
lead that includes one or more stimulation electrodes. The
stimulation electrodes may be located adjacent to the sensors
proximate to the distal end of the lead, interspersed with the
sensors at the distal end, for example, in an alternating fashion,
or otherwise positioned anywhere along the length of the lead.
Another example of a combination lead in accordance with the
present invention is a fluid delivery device for delivering one or
more drugs that carries the sensors at the distal end.
[0016] A combination lead that may be particularly advantageous
includes stimulation electrodes or openings for delivering drugs
along a medially located portion of the lead. In this case, the
lead can be positioned so that when it is fully inserted, the
stimulation electrodes or openings for delivering drug therapy are
positioned at the target stimulation site, such as proximate to the
S3 sacral nerve, and the sensors are positioned at the target
sensing site, such as proximate to a portion of the bladder,
intestines, or rectum.
[0017] In one embodiment, the invention is directed toward a method
comprising receiving a sensor signal that varies as a function of a
parameter associated with a voiding event of a patient, determining
whether the voiding event occurred based on the sensor signal,
receiving input from the patient, where the input comprises a
patient defined action that is received via a device implanted
within the patient, and associating the input with an occurrence of
the voiding event.
[0018] In another embodiment, the invention is directed toward a
system comprising a sensor that generates an electrical signal that
varies as function of a parameter associated with a voiding event
of a patient, a processor that processes the electrical signal to
detect the voiding event, and an implantable input mechanism
configured to receive an input from the patient. The input
comprises a patient defined action. The processor associates the
input with the detected voiding event.
[0019] In another embodiment, the invention is directed toward a
computer-readable medium comprising instructions that cause a
processor to receive a sensor signal that varies as a function of a
parameter associated with a voiding event of a patient, determine
whether the voiding event occurred based on the sensor signal,
receive input from the patient via a patient defined action that is
received via a device implanted within the patient, and determine
whether the voiding event was a controlled event or an involuntary
event based on the input.
[0020] In various embodiments, the invention may provide one or
more advantages. For example, the automatic voiding diary records
voiding events without the need for significant patient interaction
and may be implanted within the patient, incorporated as part of a
personal electronic device, or implemented as a wearable electronic
device that automatically generates a voiding log. This may
eliminate the need for a patient to keep a manual diary and,
therefore, may provide a more objective and accurate log for review
by a clinician and therapy based on the log.
[0021] In addition, information from the automatic voiding diary
may be used in a closed loop system implemented by the automatic
voiding diary or associated IMD to automatically adjust stimulation
parameters based on the measured parameters, detected voiding
events or an identification of voiding events as controlled or
involuntary. In this manner, the automatic voiding diary may
provide adjustment to the therapy in response to detecting an
involuntary voiding event. Consequently, the automatic voiding
diary may, for example, control a stimulator that stimulates a
nerve or muscle of the patient to prevent the patient from
unintentionally voiding his or her bladder in response to detecting
voiding events.
[0022] In embodiments in which the automatic voiding diary records
identification data for voiding events based on a patient defined
action, the additional input may be useful for diagnosis of the
patient and selection of a therapy for the patient.
[0023] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a schematic diagram illustrating an embodiment of
a system including an implantable medical device (IMD) configured
to operate as an automatic voiding diary and deliver therapy for
treating urinary incontinence.
[0025] FIG. 2 is a block diagram illustrating components of the IMD
of FIG. 1.
[0026] FIG. 3 is a block diagram illustrating components of a
programmer associated with the IMD of FIG. 1.
[0027] FIG. 4 is a schematic diagram illustrating a system that
includes separate devices implanted within a patient, where the
devices are configured to deliver therapy to treat urinary
incontinence and operate as an automatic voiding diary.
[0028] FIG. 5 is a block diagram illustrating components of the
automatic voiding diary device in FIG. 4.
[0029] FIG. 6 is a schematic diagram illustrating a system
including an embodiment of an external device configured to operate
as an automatic voiding diary.
[0030] FIG. 7 is a block diagram illustrating components of the
external device of FIG. 6.
[0031] FIG. 8 is a conceptual diagram illustrating a system
including another embodiment of an external device configured to
operate as an automatic voiding diary.
[0032] FIG. 9 is block diagram illustrating components of the
example external device in FIG. 8.
[0033] FIG. 10 is a flow diagram illustrating an example technique
for automatically detecting voiding events and recording voiding
information for the detected voiding events.
[0034] FIG. 11 is a flow diagram illustrating an example technique
for calibrating an automatic voiding diary device in accordance
with an embodiment of the invention.
[0035] FIG. 12 is a schematic diagram illustrating an example IMD
that records voiding information based on a patient defined
action.
[0036] FIG. 13 is a schematic diagram illustrating various
components of the example IMD in FIG. 12.
[0037] FIG. 14 is a flow diagram an example technique for recording
voiding information based on a patient defined action.
[0038] FIGS. 15A and 15B are schematic diagrams illustrating a
system including an IMD configured to operate as an automatic
voiding diary and coupled to an implantable medical lead that
carries one or more sensors for detecting urinary and fecal voiding
events, respectively.
[0039] FIG. 16 is a perspective view of an example medical lead
that may be used for detecting voiding events and deliver therapy
to a patient for urinary or fecal incontinence.
[0040] FIG. 17 is a block diagram illustrating various components
of an IMD and the implantable medical lead of FIG. 16.
[0041] FIG. 18 is a flow diagram illustrating an example technique
for implanting an implantable medical lead for detecting voiding
events and delivering therapy to a patient for urinary or fecal
incontinence.
DETAILED DESCRIPTION
[0042] Urinary and fecal incontinence are conditions that affect
the quality of life and health of many people. Urinary incontinence
is an inability to control urinary function and is a common problem
afflicting people of all ages, genders, and races. Likewise, fecal
incontinence is an inability to control bowel movements. A variety
of disorders may compromise performance of the urinary tract and
anal sphincter and, thus, contribute to incontinence. Many of the
disorders may be associated with aging, injury, or illness.
[0043] Tracking voiding events may be important for diagnosing a
patient's condition, such as by determining the number of voluntary
or involuntary events a patient has within a certain time range
(e.g., a day or a week), or for selecting an appropriate course of
treatment, which may or may not include stimulation therapy, for
the patient to treat the incontinence. However, manually tracking
voiding events, e.g., keeping a written or electronic voiding
diary, is often undesirable or inconvenient for the patient.
Keeping the voiding diary takes time out of the patient's day and
may be noticed by other people, causing embarrassment to the
patient. In addition, manually tracking voiding events may result
in voiding information errors. For example, the patient may
inadvertently forget to record an event, fail to objectively
describe the event, or even purposefully keep false voiding
information in the diary. These problems with a voiding diary may
undermine the ability of the clinician to properly assess patient
condition and prescribe an effective therapy.
[0044] Systems described herein include a device that is configured
to operate as an automatic voiding diary for recording voiding
events without the need for significant patient interaction. The
device is referred throughout this disclosure as an automatic
voiding diary and generally described for recording urinary voiding
events. However, it should be understood that the automatic voiding
diary may also be configured to record fecal voiding events.
[0045] FIG. 1 is a schematic diagram illustrating a system 2 that
includes an implantable medical device (IMD) 12 configured to
automatically record urinary voiding events and deliver therapy to
patient 10 for urinary incontinence. IMD 12 may also be configured
to provide an alert for patient 10 to seek medical follow-up in
response to, for example, detecting that the therapy delivered is
inadequate or the efficacy of therapy is degrading. The alert may
be provided via patient programmer 16 or other patient monitoring
system (not shown). As shown in FIG. 1, system 2 includes IMD 12
and patient and clinician programmers 16 and 18, respectively, in
wireless communication with IMD 12. IMD 12 delivers therapy to
patient 10 for urinary incontinence via therapy element 15 and
includes automatic voiding diary 14. In particular, automatic
voiding diary 14 automatically records voiding events without the
need for significant patient interaction. The voiding diary may be
used to determine the efficacy of the therapy, e.g., by determining
the number of controlled voiding events and involuntary voiding
events during therapy delivery or by determining the therapy
program being implemented by IMD 12 at the time the involuntary
voiding events occurred. In addition, the voiding diary 14 may be
used to manually or automatically adjust therapy parameters with
which IMD 12 delivers therapy to patient 10 or trigger therapy
delivery in response to detecting a voiding event.
[0046] In general, automatic voiding diary 14 detects urinary
voiding events by receiving one or more electrical signals from a
sensor that vary as a function of a parameter associated with a
voiding event and processes the electrical signals generated by the
one or more sensors to generate voiding information. The voiding
information may be recorded for the detected urinary voiding
events. The parameter associated with a voiding event (i.e., a
voiding parameter) may include, for example, pelvic nerve activity,
the content of leaked fluid, amount of leaked fluid, temperature of
leaked fluid, pH of the leaked fluid, bladder volume, bladder
pressure, sphincter pressure, bladder impedance, volume of voided
fluid, or a sound associated with the voiding event. The one or
more sensors may generate the signal may include, for example, one
or more microphones, pressure sensors, flow sensors, strain gauges,
sensing electrodes, temperature sensors, any other type of sensor
used for generating a signal indicative of a parameter associated
with voiding events, or any combination thereof. In the case of
measuring bladder impedance, the impedance may be measured between
at least two electrodes positioned at different locations on the
bladder.
[0047] The voiding information may be wirelessly transmitted to one
or both of patient and clinician programmers 16 and 18 or another
computing device. Patient and clinician programmers 16 and 18 may
present the voiding information to an authorized user, e.g., a
patient and clinician, respectively, as a voiding diary or log. As
described in further detail in this disclosure, a patient may
review the voiding diary to manually adjust therapy parameters
within pre-determined settings and/or confirm the voiding
information. A clinician may review the voiding information for
diagnostic purposes, i.e., monitor the condition of the patient, to
evaluate the efficacy of IMD 12 or of particular therapy programs
including one or more therapy parameters implemented by IMD, or to
manually adjust therapy parameters. Patient and clinician
programmers 16 and 18 may also, in response to receiving the
voiding information, automatically adjust one or more therapy
parameters based on the received voiding information.
[0048] In FIG. 1, automatic voiding diary 14 includes a microphone
(not shown) that translates sounds associated with a urinary
voiding event into an electrical signal. The microphone may be a
crystal microphone, condenser microphone, a ribbon microphone, or
other type of microphone suitable for implantation within patient
10. The microphone may be positioned on or within the housing of
IMD 12 or carried on therapy element 15, which may be, e.g., a
medical lead or a fluid delivery catheter. In particular, the
microphone in automatic voiding diary 14 may translate internal or
external sounds into an electrical signal. Internal sounds may be
sounds internal to patient 10, such as sounds produced by bladder
20, urinary tract 22, or other organs and tissue (not shown) that
produce a sound associated with a urinary voiding event. External
sounds may be sounds produced by patient 10 or the environment
during a voiding event. An external sound, for example, may be a
sound produced by urine being voided into a toilet, a toilet
flushing, urine exiting urinary tract 22, urine being voided into
an undergarment, or other sounds associated with a urinary voiding
event.
[0049] Examples of systems and methods that include a microphone as
a sensor to generate an electrical signal that varies as a function
of a sound associated with a voiding event is described in
commonly-assigned U.S. patent application Ser. No. ______ by Martin
T. Gerber et al., entitled, "AUTOMATIC VOIDING DIARY," (attorney
docket number 1023-631US01/P0028138.00) and filed on the same date
as the present disclosure, the entire content of which is
incorporated herein by reference.
[0050] In embodiments in which automatic voiding diary 14 is used
for recording fecal voiding events, internal sounds may include
sounds produced by the rectum (not shown), intestines (not shown),
such as sounds produced by fecal matter moving through the bowel
during a voiding event, or other organs and tissue (not shown) that
produce sounds associated with a fecal voiding event. External
sounds include sounds produced by patient 10 or the environment
during a fecal voiding event, such as feces being voided into a
toilet, a toilet flushing, feces exiting the rectum, feces being
voided into an undergarment, or other sounds associated with a
fecal voiding event.
[0051] IMD 12 may typically be subcutaneously implanted the body of
patient 10, e.g., in the lower back, lower abdomen, or buttocks of
patient 10. When implanted at one of these locations, a microphone
positioned on or within the housing of IMD 12 may be capable of
reliably picking up internal and/or external sounds associated with
voiding events. Alternatively, the microphone may be carried on
therapy element 15 coupled to IMD 12. In this case, therapy element
15 and, more particularly, the microphone carried by therapy
element 15 is positioned at a target sensing site that may enable
the microphone to pick up internal or external sounds associated
with voiding events. However, in some embodiments, IMD 12 may be
implanted at the target sensing site, which may be proximate to a
portion of bladder 20, urinary tract 22, or other organs or tissue
that produce sounds associated with voiding events. In those
embodiments, a microphone carried on or within the housing of IMD
12 may be placed at the target sensing site without the need for
therapy element 15 or another member coupling the microphone to IMD
12. In another example embodiment, the microphone may be a wireless
microphone configured to be implanted within patient 10 and
communicate with IMD 12 or an external device, such as patient and
clinician programmers 16 and 18.
[0052] In any case, the location at which the microphone is
positioned may affect the quality of the signal produced by the
microphone. For this reason, it may be desirable to position IMD
12, and in the case of an implanted microphone carried on therapy
element 15 coupled to IMD 12, implant the therapy element 15 such
that the microphone is proximate to the source of the sound that is
to be detected in order to strengthen the signal produced by the
microphone. In addition, the position of the microphone relative to
the source of the sound (or near the source of multiple sounds) may
allow the microphone to pick-up sounds associated with a voiding
event without being significantly affected by unwanted noises.
Unwanted noises are generally sounds that are not associated with a
voiding event, such as noises produced by the digestive system of
patient 10 or the environment surrounding patient 10.
[0053] The electrical signal generated by the microphone, also
referred to as the sensor signal, is processed to detect voiding
events. Processing the sensor signal may, for example, involve
processing the signal to remove noise, i.e., unwanted signal
components, and processing the signal to identify a voiding
signature. In some embodiments, the voiding signature includes a
characteristic of an electrical signal that is generated prior to
or during an actual voiding event for a patient or for multiple
patients. The voiding signature may be individualized to a
particular patient or may be applicable to more than one patient.
In one embodiment, the voiding signature used to detecting voiding
events is an example signal generated by the microphone during an
actual voiding event. This example signal is referred to as a
signal template and may be obtained during an initial training or
calibration session for voiding diary 14. The training session may
take place in a clinical environment with controlled conditions.
For example, the bladder of patient 10 may be manually filled and
the corresponding voiding event may be recorded using automatic
voiding diary 14. The signal may be examined and, if determined to
be satisfactory, may be stored and used as a signal template for
detecting voiding events. Multiple signals may also be generated
during the voiding diary 14 training session and averaged or
otherwise analyzed to generate a signal template that is
representative of a voiding event for the patient.
[0054] In general, voiding diary 14 may include a processor that
amplifies, samples, filters, or otherwise processes the sensor
signal to remove noise and identify a voiding signature in the
sensor signal. Processing the sensor signal to remove noise from
the signal may enable voiding diary to detect voiding events more
reliably. Noise may be introduced into the sensor signal by other
sounds that are detected by the microphone or introduced into the
sensor signal by the microphone itself. Thus, voiding diary may
include a processor that filters the sensor signal before
processing the signal to identify a voiding signature. The sensor
signal may be filtered using various signal processing techniques
that may be applied to suppress signal components at one or more
frequencies or range of frequencies.
[0055] In one example embodiment, processing the sensor signal to
identify a voiding signature in the sensor signal involves
temporally correlating the sensor signal with a signal template.
This may be achieved by sampling the signal with a sliding "window"
that defines a time range, and comparing the sample of the signal
to a signal template to identify a signal that correlates well with
the template. For example, a processor of IMD 12 or an external
device may perform a correlation analysis by moving a window along
a digitized plot of the amplitude of the signal generated by the
microphone at regular intervals to define a sample of the signal
from the microphone. The sample window is slid along the plot until
a correlation is detected between the waveform of the signal
template and the waveform of the sample of the microphone signal
defined by the window. By moving the window at regular time
intervals, multiple sample periods are defined. The correlation may
be detected by, for example, matching multiple points between the
template waveform and the waveform of the plot of the signal from
the microphone over time, or by applying any suitable mathematical
correlation algorithm between the sample in the sampling window and
a corresponding set of samples stored in the signal template.
[0056] In some embodiments, processing the sensor signal to detect
voiding events may be more complex than correlating the sensor
signal with a signal template. That is, rather than comparing the
entire sensor signal waveform to the signal template, preliminary
signal processing may be applied to locate portion of the sensor
signal that exhibits an increased likelihood of containing a
voiding signature. In fact, the sensor signal may be substantially
continuous and generated over large periods of time (e.g., over
days, weeks or more) and, therefore, include large portions that do
not correspond to voiding events. As a result, a less complex
processing technique may be used to first determine the likelihood
that a portion of the sensor signal contains a voiding signature.
Example processing techniques that may be used during a preliminary
analysis of the sensor signal include comparing an amplitude of the
sensor signal to a threshold value. The amplitude may be an
amplitude of a particular frequency component. Based on the
comparison to the threshold value, the sensor signal may then be
correlated with the signal template. Using a combination of
processing techniques in this way may conserve battery power, which
may be important to the life of IMD 12 because it may be expected
to operate for weeks, months, or years on a single power
source.
[0057] The processing techniques described in this disclosure
should not be considered limiting of the invention as broadly in
this disclosure in any way. Rather, the described processing
techniques are merely exemplary and are intended to provide
descriptive examples without taking focus away from the primary
features of the invention.
[0058] When a voiding event is detected, automatic voiding diary 14
stores voiding information associated with the detected voiding
event in local memory within voiding diary 14 (or IMD 12 in
embodiments in which IMD 12 includes voiding diary 14). The voiding
information may include, for example, the corresponding portion of
the sensor signal that includes the voiding signature or data that
indicates the occurrence of the detected voiding event. The voiding
information may also include a timestamp that corresponds to the
time at which the voiding event was detected.
[0059] Furthermore, in some embodiments, system 2 or, more
particularly, IMD 12, may include additional sensors (not shown)
that monitor other voiding parameters. Examples of other voiding
parameters include the content of voided fluid, amount of voided
fluid, temperature of voided fluid, pH of voided fluid, and the
like. Accordingly, the additional sensors may include one or more
of impedance sensors, strain gauges, temperature sensors,
accelerometers, pH sensors, chemical sensors, and the like. In such
embodiments, automatic voiding diary 14 stores voiding information
that corresponds to these voiding parameters.
[0060] In operation, automatic voiding diary 14 detects voluntary
or controlled events and involuntary or incontinence events. It is
typically important to distinguish between voluntary and
involuntary voiding events for diagnostic purposes. For this
reason, the voiding information recorded by automatic voiding diary
14 may include information that identifies a detected event as a
voluntary or involuntary event.
[0061] In one example embodiment, patient 10 may enter input into
patient programmer 16 to identify a voiding event as a controlled
(i.e., voluntary) or involuntary event. Patient 10 may, for
example, activate one or more buttons, use a stylus, mouse, or
other peripheral device to enter input on a graphical user
interface. Patient programmer 16 may then, in response to receiving
the input, wirelessly transmit corresponding identification
information (e.g., an indication of whether the voiding event was
voluntary or involuntary) to automatic voiding diary 14, which may
associate the received identification information with the
corresponding voiding information. In embodiments in which
automatic voiding diary 14 transmits the voiding information to
patient programmer 16 for storage, patient programmer 16 may store
the identification information with or without transmitting the
information to automatic voiding diary 14 and may associate the
voiding information with the voiding event identification
information.
[0062] Other techniques for generating identification information
for voiding events may be employed in other embodiments. For
example, in one embodiment, an involuntary voiding event may be
detected via one or more sensors incorporated into an undergarment,
as described in commonly-assigned U.S. patent application Ser. No.
11/414,504 to John C. Rondoni et al., entitled, "VOIDING DETECTION
WITH LEARNING MODE" and filed on Apr. 28, 2006, the entire content
of which is incorporated herein by reference. The one or more
sensors detect the presence of fluid which indicates that wetting,
and most likely, an involuntary voiding event has occurred. In some
cases, the sensor may be also capable of also detecting fluid pH or
other characteristic of the fluid to identify that the fluid is
urine. In some embodiments, a pocket that holds a sensor may also
include absorption material that absorbs voided urine, such that
the undergarment is similar to a diaper or protective garment.
[0063] In some embodiments, automatic voiding diary 14 includes
features for storing voiding information, such as information that
identifies a detected voiding event as a voluntary or involuntary
event, based on a patient defined action, such as patient 10
tapping on the skin located above IMD 12. Such an example
embodiment is illustrated and described in detail in FIGS. 12 and
13.
[0064] Various embodiments of automatic voiding diary 14 may be
used for storing and retrieving the voiding information. In one
example embodiment, automatic voiding diary 14 automatically
records voiding information in local memory and wirelessly
transmits the voiding information to patient programmer 16,
clinician programmer 18, or both. Automatic voiding diary 14 may
transmit the voiding information on request, periodically, or when
local memory is full. Alternatively, automatic voiding diary 14 may
transmit the voiding information substantially continuously.
[0065] In some embodiments, patient programmer 16 and clinician
programmer 18 may retrieve information stored within automatic
voiding diary 14 at any time, for example, by transmitting a
wireless request signal to automatic voiding diary 14. In response
to the request, automatic voiding diary 14 wireless transmits the
voiding diary to the appropriate programmer which displays the
voiding information as a diary or log to the user.
[0066] In other embodiments, automatic voiding diary 14 may
transmit the stored voiding information to programmers 16 and 18
periodically. For example, automatic voiding diary 14 may store
voiding information for a pre-determined period of time, such as
approximately one day, and transmit the voiding information at the
end of the time period. In this case, automatic voiding diary 14
may erase or record over the transmitted voiding information.
[0067] In another example, automatic voiding diary 14 may transmit
the voiding information to one or both of programmer 16 and 18 when
local memory is full or near full capacity. In this case, automatic
voiding diary 14 may erase or record over the stored data when the
voiding information has been successfully transmitted. In this way,
automatic voiding diary 14 may efficiently store voiding
information and then "dump" the stored information to patient
programmer 16 for long term storage. Alternatively, automatic
voiding diary 14 may store voiding information until local memory
is full or near capacity and transmit all subsequent voiding
information to patient programmer 16.
[0068] In an additional example, automatic voiding diary 14 may
store little or no voiding information. In this case, diary 14
processes the sensor signal to detect a voiding event, generate the
voiding information, and immediately transmits the voiding
information to patient programmer 16 for long term storage. The
voiding information may be stored in memory of diary 14 for a short
period of time or may be transmitted substantially directly to
patient programmer 16. As a result, diary 14, in this case, may
require a relatively small amount of memory.
[0069] The amount of voiding information stored in automatic
voiding diary 14 is related to the size of local memory of
automatic voiding diary 14. Storing a smaller amount of voiding
information in local memory of automatic voiding diary 14 allows
the size of diary 14 and, thus, the size of IMD 12 to be reduced.
The tradeoff between size and the memory capacity of automatic
voiding diary 14 is a design choice that may be affected by various
other aspects of system 2.
[0070] In general, programmers 16 and 18 provide an easy to user
interface for viewing the voiding diary and adjusting and/or
programming therapy. The interface may include tools for navigating
and customizing the display. For example, programmers 16 and 18 may
provide a scroll bar or other mechanism for navigating the voiding
diary and a menu or selection mechanism for specifying the
information that is to be displayed in the voiding diary.
Programmers 16 and 18 communicate with IMD 12 via a wireless
interface. Example wireless interfaces include wireless telemetry,
Bluetooth, IEEE 802.11 (a), (b), (g), Medical Implant Communication
Services (MICS), and other standard proprietary wireless
interfaces.
[0071] Patient 10 may use patient programmer 16 to review voiding
information and, in some embodiments, enter input to verify that
the information is correct. Patient 10 may also user programmer 16
to identify an abnormal intake of fluid, such as a drinking binge,
or other event that may affect a normal voiding pattern. In this
way, patient 10 can use patient programmer 16 to ensure that the
data stored in voiding diary 14 is accurate.
[0072] For example, after patient 10 voids bladder 22 voluntarily
or involuntarily, patient 10 may use programmer 16 to verify that
automatic voiding diary 14 detected the event and identify or
categorize the event as a controlled or involuntary event.
Verifying the information may involve entering input into
programmer 16. For example, patient programmer 16 may prompt
patient 10 via one or more questions, to which patient 10 may enter
responses via a user interface of patient programmer 16. In the
event that patient 10 indicates that the voiding information
generated by automatic voiding diary 14 is incorrect, automatic
voiding diary 14 may discard the incorrect information or,
alternatively, store additional data that indicates that patient 10
identified the information as being incorrect. Storing this data
may prevent or deter patient 10 from falsely modifying information
because of embarrassment or other reasons since the clinician will
be able to determine if the information has been modified.
[0073] A clinician or other authorized user may use clinician
programmer 18 to view the voiding diary and use the voiding diary
to identify a condition afflicting patient 10 or monitor a
condition of patient 10. In this way, a clinician can use
programmer 18 as a diagnostic tool to determine the appropriate
course of treatment, which may or may not include therapy, or
determine the efficacy of treatment. As an example, a clinician may
diagnose that patient 10 suffers from nocturnal enuresis by
examining the time and nature of voiding events over a period of
time within the voiding diary. Based on the diagnosis, the
clinician may prescribe therapy in the form of stimulation therapy,
drug therapy, or a combination of both. The clinician may then use
programmer 18 at a later date to view the voiding diary to evaluate
the efficacy of the treatment.
[0074] Additionally, a clinician or other authorized user may use
clinician programmer 18 to program therapy for patient 10, such as
therapy for urinary incontinence. Programmer 18 may transmit one or
more programming instructions to IMD 12 via wireless communication
signals. The programming instructions may specify one or more
therapy programs that IMD 12 may deliver therapy in accordance
with, where each therapy program defines one or more therapy
parameters. Examples of therapy parameters include voltage or
current amplitude, pulse width or pulse frequency of electrical
stimulation, or drug bolus size, drug concentration or frequency of
drug delivery. The type of therapy parameters depends on the type
of therapy delivered by IMD 12.
[0075] In the example illustrated in FIG. 1, programmer 18 may be
configured to program IMD 12 to deliver stimulation therapy, drug
therapy, or a combination of both according to one or more therapy
programs. Accordingly, in some embodiments, IMD 12 may operate as
an implantable neurostimulator (INS) that delivers electrical
stimulation therapy for incontinence, while in other embodiments,
IMD 12 may be a drug delivery device that delivers one or more
drugs. In another embodiment, IMD 12 may be configured to operate
as an INS and a drug delivery device.
[0076] Accordingly, therapy element 15 in FIG. 1 may represent a
lead carrying one or more electrodes that delivery stimulation in
the form of electrical pulses or a fluid delivery device, such as a
catheter, that delivers one or more drugs. In some embodiments,
therapy element 15 may carry electrodes and deliver drugs.
Therefore, therapy element 15 should not be considered limiting of
the invention as broadly described in this disclosure. Instead it
is the purpose of therapy element 15 to represent one or many
therapy elements that deliver therapy from IMD 12 to a target
tissue site within patient 10 in the form of electrical
stimulation, drugs, or a combination of both. Therefore, it should
be understood that FIG. 1 illustrates one of the many example
embodiments that fall within the scope of the invention as broadly
described in this disclosure.
[0077] Programming therapy may involve selecting or adjusting
stimulation parameters or drug delivery parameters. As previously
described, example stimulation parameters include an electrode
configuration, a pulse rate, a pulse width, and voltage amplitude
or current amplitude. Electrode configuration may refer to both a
combination of selected electrodes and polarities of the
electrodes, i.e., as a cathode or anode. Electrical stimulation may
be delivered in accordance with one or more programs. Programs may
deliver electrical stimulation in a variety of different modes,
such as a continuous mode, in a series of bursts, or a combination
of both. In a similar manner, a clinician may specify a set of
parameters for drug delivery that includes selecting which drug or
mixture of drugs to deliver, as well as the dosage and rate at
which to deliver the selected drug or drugs.
[0078] In practice, a clinician may use clinician programmer 18 to
select a set of initial therapy parameters and view the voiding
diary after patient 10 has been subjected to therapy for a period
of time. By comparing the voiding information before and after
therapy, the clinician can determine the efficacy of the treatment
and may manually adjust stimulation parameters in an attempt to
improve the efficacy of the treatment. Patient programmer 16 may
also provide certain limited capabilities to patient 10. For
example, patient 10 may use programmer 16 to select particular
programs or vary the intensity of therapy within a pre-determined
range. Further, patient programmer 16 or IMD 12 itself may
automatically adjust parameters according to the detected voiding
information. For example, in response to detecting a voiding event
and associating the voiding event with identification information
that indicates the voiding event was involuntary, IMD 12 may
automatically increase the intensity of therapy or otherwise adjust
the therapy parameters to prevent or reduce involuntary voiding
from occurring in the future.
[0079] Stimulation parameter adaptation logic that may be
implemented by IMD 12, clinician programmer 18 or patient
programmer 16 is discussed in commonly-assigned U.S. patent
application Ser. No. 11/117,058, entitled, "IMPLANTABLE MEDICAL
DEVICE PROVIDING ADAPTIVE NEUROSTIMULATION THERAPY FOR
INCONTINENCE," and filed on Apr. 28, 2005, which is incorporated
herein by reference in its entirety.
[0080] It should be understood that system 2 as illustrated in FIG.
1 depicts one of many example systems. That is, system 2, as
depicted in FIG. 1, should not be considered limiting of the
invention as broadly described in this disclosure in any way.
Instead, the purpose of system 2 is to provide one example
embodiment suitable for broadly describing features of the
invention.
[0081] For example, although FIG. 1 illustrates a single device,
i.e., IMD 12, which operates as a therapy delivery device and an
automatic voiding diary, other example systems may include a
therapy delivery device and a separate IMD configured to operate as
an automatic voiding diary. In other words, the therapy delivery
device and the automatic voiding diary device may be separate
devices implanted within the patient, and in some embodiments, the
therapy delivery device and automatic voiding diary may communicate
via wired or wireless communication techniques. The devices may be
implanted proximate to one another or at different locations within
the patient. A system that includes a therapy delivery device and a
separate automatic voiding diary device may be advantageous when
the implant site for delivering therapy is different than the
implant site for sensing sounds associated with a voiding
event.
[0082] In other example embodiments, the automatic voiding diary
device may be an external device. In such embodiments, the
automatic voiding diary device may be incorporated with patient
programmer 16 or implemented as a dedicated external device. In
either case, it may desirable for patient 10 to carry the external
device substantially continuously during a voiding event
information gathering period in order to obtain accurate voiding
information. Additionally, it may be desirable for patient 10 to
carry the external device may be required to be close to the body
for the microphone to generate a signal based on an internal or
external sound associated with a voiding event. The external device
may be implemented in various ways. For example, the external
device may be taped to the skin of patient 10 or an undergarment
worn by patient 10, trapped between clothing and the skin of
patient 10, attached to the inside of clothing worn by patient 10,
sutured to the skin of patient 10, held to the skin of patient 10
via a strap, or may otherwise be wearable by patient 10.
[0083] In further example embodiments, the automatic voiding diary
is not necessarily used in combination with a therapy delivery
device. A system that does not include a therapy delivery device
may be used as a diagnostic tool to identify and/or monitor the
condition of the patient and also to determine if therapy would
benefit the patient and which therapy would be most beneficial.
[0084] It is also contemplated that system 2 or other embodiments
of the invention may be used in combination with one or more
additional sensors that measure other voiding parameters (i.e.,
parameters associated with voiding). The monitoring of electrical
signals indicative of voiding parameters may be useful for
analyzing a patient's condition or therapy program. The additional
sensors may include one or more of pressure sensors, impedance
sensors, strain gauges, temperature sensors, accelerometers, pH
sensors, chemical sensors, and the like. Accordingly, other voiding
parameters of interest may include the content of leaked fluid,
amount of leaked fluid, temperature of leaked fluid, pH of the
leaked fluid, bladder pressure, and so forth. In addition, other
parameters associated with a voiding event may also be monitored
and stored in the voiding diary. For example, the activity and
posture of patient 10 may also be stored in the voiding diary.
[0085] Automatic voiding diary 14 may store the output of the
additional sensors in the voiding diary. Accordingly, a clinician
may use clinician programmer 18 to view the voiding diary and
adjust therapy parameters based on information relating to one or
more voiding parameters stored within the voiding diary.
Additionally, patient programmer 16, clinician programmer 18, or
both may automatically adjust therapy parameters based on the
information in the voiding diary. For example, the clinician or
programmer 16 and 18 may increase the intensity of stimulation
based one or more voiding parameters, such as the amount of fluid
leaked, to prevent or reduce involuntary voiding.
[0086] FIG. 2 is a block diagram illustrating various components of
IMD 12. As shown in FIG. 2, IMD 12 includes components for
automatic voiding diary 14 and components for therapy delivery
device 30. In other embodiments, however, the components for
automatic voiding diary 14 and therapy delivery device 30 may be
enclosed in separate housings. The components of automatic voiding
diary 14 record information associated with a voiding event without
the need for significant interaction from patient 10. The
components of therapy delivery device 30 deliver therapy to patient
10 to control urinary or fecal incontinence.
[0087] Automatic voiding diary 14 includes a sensing circuitry 40,
sensor 42, processor 44, memory 46, and clock 48. In general,
sensing circuitry 40 detects a voiding event based on the output of
sensor 42, i.e., the electrical signal generated by sensor 42.
Memory 46 stores voiding information under the control of processor
44. Processor 44 may obtain a clock signal from clock 48 to
associate a timestamp with the voiding information for a detected
voiding event stored in memory 46. Memory 46 may include any
combination of volatile, non-volatile, removable, magnetic,
optical, or solid state media, such as read-only memory (ROM),
random access memory (RAM), electronically-erasable programmable
ROM (EEPROM), flash memory, or the like. Processor 44 may include a
microprocessor, microcontroller, digital signal processor (DSP),
application specific integrated circuit (ASIC), field programmable
gate array (FPGA), discrete logic circuitry, or a combination of
such components.
[0088] In one embodiment, sensor 42 is a microphone that generates
an electrical signal in accords with internal or external sounds
associated with voiding events and may be positioned within or on
the housing of IMD 12. Alternatively, sensor 42 may be carried
within or on a lead that extends from IMD 12 or wirelessly coupled
to IMD 12. In another embodiment, sensor 42 may be a wireless
microphone implanted within patient 10 and configured to wirelessly
communicate with IMD 12. As previously described, sensor 42 may be
a crystal microphone, condenser microphone, a ribbon microphone, or
other type of microphone suitable for implantation within patient
10.
[0089] In embodiments in which sensor 42 is a microphone, sensor 42
may generate a signal that varies as a function of internal sounds,
such as sounds produced by bladder 20 (FIG. 1), urinary tract 22
(FIG. 1), rectum (not shown), intestines (not shown), such as
sounds produced by fecal matter moving through the bowel during a
voiding event, or other organs and tissue (not shown) of patient 10
that produce sounds associated with a urinary or fecal voiding
event. In addition to or instead of generating the signals that
vary as a function of internal sounds, sensor 42 may generate a
signal that varies as a function of sounds external to patient 10,
such as sounds produced by urine or feces being voided into a
toilet, a toilet flushing, fluid exiting the opening of the urethra
(FIG. 1), urine or feces being voided into an undergarment, a voice
command, or other sound associated with a urinary or fecal voiding
event.
[0090] The electrical signal output by sensor 42 may be amplified,
filtered, and otherwise processed by sensing circuitry 40. As
described above, sensing circuitry 40 may process the signal to
remove unwanted signal components to more reliably detect a voiding
event. Removing unwanted signal components, e.g., by filtering the
output of sensor 42, may increase the likelihood of accurately and
reliably detecting a voiding event. Unwanted signal components may
include noise introduced by the signal path and signal components
that result from sounds that are not associated with a voiding
event but are picked up by sensor 42. These sounds may include
other sounds internal to patient 10, such as digestive sounds,
heart sounds, breathing sounds, and the like as well as sounds
external to patient 10, i.e., sounds produced by the environment
surrounding patient 10.
[0091] To detect a voiding event, sensing circuitry 40 may, for
example, utilize a correlation or comparison technique, such as the
temporal correlation technique described above. In particular,
sensing circuitry 40 may apply the detection technique to the
processed signal in which the unwanted signal components have been
removed, i.e., the "clean" sensor signal. A correlation technique
may involve correlating a sample of the signal generated by sensor
42 to a signal template stored in memory 46 in order to detect the
presence of a voiding signature in the signal generated by sensor
42. The signal template may be generated based on one or more
example signals that are produced by sensor 42 during a trial or
test period. During the trial or test period, patient 10 may be
instructed to void under controlled conditions. That is, patient 10
may void at a known time so the signal can be analyzed.
[0092] The voiding signature may be characterized by one or more
signal characteristics, e.g., a particular frequency, amplitude,
pattern, trend, or waveform shape, duration, or other signal
characteristic. As an example, a sound associated with a voiding
event, such as urine or feces being voiding into a toilet, may
exhibit a particular frequency that lasts for several seconds or
more. As another example, a sound produced by a muscle that
contracts and relaxes to control voiding may be characterized by
one or more pulses of sound at a particular frequency. In this
case, the period of time between pulses may also be characteristic
of the voiding signature.
[0093] Sensing circuitry 40 may employ various signal processing
techniques to detect a voiding signature in the output of sensor
42. Example, correlation techniques may be performed in a time or
frequency domain. In some cases, the frequency domain may be more
revealing of signal characteristics than the time domain. Frequency
analysis techniques involve converting the time domain signal
produced by sensor 42 into a frequency signal. This can be achieved
by applying a Fast Fourier Transform to the output of sensor 42,
which is a time domain signal. Frequency analysis techniques may
then be used to detect a voiding event in the frequency signal.
Example frequency analysis techniques involve determining the power
of the signal for particular frequency components.
[0094] Additional signal processing techniques may be used to
conserve power. That is, because the detection processing
techniques may be complex and consume significant power, sensing
circuitry may also employ low power signal detection techniques. As
an example, sensing circuitry 40 may compare the output of sensor
42 to a threshold value. The threshold value may be the total power
of the sensor signal or power of a particular frequency. This
comparison determines the likelihood that a particular portion of
the sensor signal contains a voiding signature. In other words,
when the amplitude of the output of sensor 42 exceeds the
threshold, that portion of the signal has an increased likelihood
of including a voiding signature. This may require little
processing power as the technique involves a simple comparison
between two values. However, when the signal exceeds the threshold,
sensing circuit 40 may apply more complex and, therefore, power
consuming detection techniques. In this way, IMD 12 may operate for
several months or years relying on power from a finite power source
(not shown), such as a rechargeable or nonrechargeable battery. In
either case, power conservation is desirable.
[0095] In addition to storing a signal template or other voiding
signatures, memory 46 of automatic voiding diary 14 may store
voiding information associated with detected voiding events. In
particular, processor 44 may generate voiding information based on
the output of sensing circuitry 40 and store the information in
memory 46. In one example, memory 46 stores data that indicates the
occurrence of the detected event. Alternatively, memory 46 may
store the actual signal generated by sensing circuitry 40 that
contains the voiding signature. A clinician may retrieve the stored
signals from memory 46 to analyze the signals. As previously
described, memory 46 may also store other voiding information
associated with a detected voiding event, such as a time stamp and
data that identifies a detected event as a voluntary or involuntary
event. In embodiments in which IMD 12 includes sensors for
recording other voiding information, such as information associated
with the contents of voided urine, this information is also stored
in memory 46.
[0096] Processor 44 may associate a timestamp with a detected
voiding event by sending a request signal to clock 48. In response
to receiving the control signal, clock 48 generates a signal that
represents the time. Alternatively, clock 48 may output the signal
to processor 44 substantially continuously and processor 44 can
examine the signal in response to detecting a voiding event. In any
case, processor 44 may use the output of clock 48 to associate a
timestamp with voiding information that is stored in memory 46.
[0097] In addition to voiding information, memory 46 may also store
instructions for execution by processor 44. Memory 46 may include
separate memories for storing instructions and voiding information.
In one example embodiment processor 44 and memory 46 may implement
loop recorder functionality in which processor 44 overwrites the
oldest contents within memory 46 with new data as storage limits
are met, thereby conserving data storage resources. Processor 44
may selectively record over the data stored within memory 46, such
as signals from sensor 42 that are not indicative of a voiding
event. Alternatively, processor 44 and memory 46 may be configured
to immediately transmit voiding information to another device, such
as patient programmer 16 or clinician programmer 18. In this case,
memory, processing, and power consumption overhead in automatic
voiding diary 14 can be substantially reduced.
[0098] As shown in FIG. 2, therapy delivery device 30 includes
therapy delivery module 32, processor 34, telemetry module 36, and
memory 38. Automatic voiding diary 14 communicates with therapy
delivery device 30 and, more particularly, telemetry module 36 to
transmit voiding information to programmers 16 and 18. In
particular, automatic voiding diary 14 may communicate with
processor 34 which controls telemetry module 36. Processor 34 may
control telemetry module 36 to transmit voiding information to an
external device, such as patient programmer 16, clinician
programmer 18, or other external device, on a continuous basis, at
periodic intervals, or upon request from an external device, such
as patient programmer 16 or clinician programmer 18.
[0099] Telemetry module 36 provides a wireless interface with
patient programmer 16 and clinician programmer 18. The wireless
interface may be one of wireless telemetry, Bluetooth, IEEE 802.11
(a), (b), (g), or other standard proprietary wireless
interfaces.
[0100] Therapy delivery device 30 delivers therapy to patient 10
for urinary incontinence via therapy element 15. Therapy element 15
may include electrodes carried on one or more leads, electrodes on
the housing of IMD 12, one or more fluid delivery devices, or any
combination thereof. Accordingly, therapy delivery module 32 may
include an implantable stimulation generator or other stimulation
circuitry that delivers electrical signals, e.g., pulses or
substantially continuous signals, such as sinusoidal signals, to
patient 10 via at least some of the electrodes of therapy element
15 under the control of processor 34.
[0101] The stimulation energy generated by therapy delivery module
32 may be formulated as stimulation energy for treatment of any of
a variety of urinary or fecal incontinence disorders. Example
stimulation therapies include delivering stimulation to nerves,
i.e., sacral or pudendal nerves, or directly to a urinary
sphincter, where the stimulation causes the urinary sphincter to
constrict and retain urine within the bladder. Electrical
stimulation may also be directed to other muscles of the pelvic
floor because some of these muscles play a role in controlling
urinary voiding events.
[0102] An exemplary range of electrical stimulation parameters
likely to be effective in treating urinary or fecal incontinence,
e.g., when applied to the sacral or pudendal nerves, are as
follows:
[0103] 1. Frequency: between approximately 0.5 Hertz (Hz) and
approximately 500 Hz, such as between approximately 5 Hz and
approximately 250 Hz or such as between approximately 10 Hz and
approximately 50 Hz.
[0104] 2. Amplitude: between approximately 0.1 volts and
approximately 50 volts, such as between approximately 0.5 volts and
approximately 20 volts or between approximately 1 volt and
approximately 10 volts. The amplitude may be representative of a
biological load between 10 ohms and approximately 10,000 ohms.
[0105] 3. Pulse Width: between approximately 10 microseconds and
approximately 5000 microseconds, such as between approximately 100
microseconds and approximately 1000 microseconds or between
approximately 180 microseconds and 450 approximately
microseconds.
[0106] Other electrical stimulation parameters may also be useful
for managing urinary incontinence.
[0107] In embodiments in which one or more fluid delivery devices
are part of therapy elements 15, therapy delivery module 32 may
include a one or more fluid reservoirs and one or more pump units
that pump fluid from the fluid reservoirs to the target site
through the fluid delivery devices. The fluid reservoirs may
contain a drug or mixture of drugs. The fluid reservoirs may
provide access for filling, e.g., by percutaneous injection of
fluid via a self-sealing injection port. The fluid delivery devices
may comprise, for example, catheters that deliver, i.e., infuse or
disperse, drugs from the fluid reservoirs to the same or different
target sites within patient 10.
[0108] Processor 34 controls therapy delivery module 32 to deliver
electrical stimulation via a programmable stimulation signal (e.g.,
in the form of electrical pulses or substantially continuous-time
signals) with pulse amplitudes, pulse widths (if applicable), and
frequencies (i.e., pulse rates) specified by programs of the
parameter set selected from memory 38. Memory 38 may store therapy
parameter sets (i.e., therapy programs) that are available to be
selected by the patient for delivery of electrical stimulation
and/or drug therapy. Memory 38 may also store schedules for
delivering therapy to patient 10. Memory 38 may include any
combination of volatile, non-volatile, removable, magnetic,
optical, or solid state media, such as ROM, RAM, EEPROM, flash
memory, or the like.
[0109] Processor 34 may also control therapy delivery module to
deliver each pulse according to a different program of the
parameter set. In some embodiments, processor 34 may control
therapy delivery module 32 to deliver a substantially continuous
stimulation waveform rather than pulsed stimulation. Additionally,
processor 34 may automatically adjust therapy parameters based on
voiding information. In this way, voiding information from
automatic voiding diary 14 may be used in a closed loop therapy
adjustment system implemented by therapy delivery device 30 to
adjust one or more therapy parameters with the goal of minimizing
the occurrence of any further involuntary incontinence events.
[0110] Processor 34 may include a microprocessor, microcontroller,
DSP, ASIC, FPGA, discrete logic circuitry, or a combination of such
components. Processor 34 is programmed to control delivery of
therapy according to a selected parameter set stored in memory 38.
Specifically, processor 34 controls therapy delivery module 32 to
deliver electrical stimulation, drug therapy, or a combination of
both. For example, processor 34 may control which drugs are
delivered and the dosage of the drugs delivered or the stimulation
parameters with which therapy delivery module 32 delivers
electrical stimulation therapy to patient 10.
[0111] A power source (not shown) delivers operating power to the
components of automatic voiding diary automatic voiding diary 14
and therapy delivery device 30. In embodiments in which automatic
voiding diary 14 and therapy delivery device 30 are located within
the same housing, the power source may be shared among devices 14
and 30. The power source may take the form of a small, rechargeable
or non-rechargeable battery, or an inductive power interface that
transcutaneously receives inductively coupled energy. In the case
of a rechargeable battery of an implanted device, the power source
similarly may include an inductive power interface for
transcutaneous transfer of recharge power.
[0112] Although FIG. 2 illustrates therapy delivery device 30 and
automatic voiding diary automatic voiding diary 14 as being
contained within a single housing, it should be understood that
therapy delivery device 30 and automatic voiding diary automatic
voiding diary 14 may be implemented as separate devices. Thus, FIG.
2 should not be considered limiting of the invention as broadly
described in this disclosure in any way. However, by incorporating
therapy delivery device 30 and automatic voiding diary automatic
voiding diary 14 in a common housing of an IMD (IMD 12), circuitry
associated with both devices 14 and 30, such as a processor and
memory, may be shared and fabricated on a single circuit board. As
a result, the IMD, i.e., IMD 12, may be substantially smaller in
size and cost less than separate devices for delivering therapy and
storing voiding information. Additionally, IMD 12 may be implanted
within patient 10 using fewer incisions and requiring less space
than separately implanting therapy delivery and voiding diary
devices.
[0113] FIG. 3 is a functional block diagram illustrating various
components of an external device 60 that may be configured to
operate as patient programmer 16 or clinician programmer 18. As
shown in FIG. 3, external device 60 includes user interface 62,
input/out module 63, processor 64, memory 68, telemetry circuit 66,
and power source 69. A clinician or patient 10 may interact with
user interface 62 in order to review the voiding log, modify a
component of the voiding log, request voiding information from IMD
12, or manually adjust one or more therapy parameters of the
stimulation and/or drug therapy. In this way, external device 60
can be viewed as patient programmer 16 or clinician programmer
18.
[0114] In general, patient programmer 16 provides limited
functionality in comparison with clinician programmer 18. As
previously described, patient 10 may interact with a patient
programmer 16 to view the voiding log and may be allowed to adjust
selected parameters. For example, patient 10 may interact with
patient programmer 16 control therapy, e.g., by selecting a program
from a limited list of programs or adjusting a parameter within a
defined range. Patient 10 may also enter input that identifies a
voiding event as a controlled or involuntary event.
[0115] In contrast, a clinician may interact with clinician
programmer 18 to program therapy in IMD 12, for example, by
selecting one or more therapy programs from memory 68. The
clinician may also define therapy parameters without being limited
to pre-defined ranges. The clinician or patient 10 may also
interact with device 60 to receive diagnostic information from IMD
12, such as the remaining life of the power source or electrode
impedance measurements if therapy element 15 or the housing of IMD
12 includes one or more sensing or stimulation electrodes.
[0116] User interface 62 may include a display and one or more
input buttons that allow clinician programmer 18 to receive input
from the clinician. The screen may be a liquid crystal display
(LCD) or touch screen. The input buttons may include a touch pad,
increase and decrease buttons, emergency shut off button, an
alphanumeric keypad or a reduced set of keys associated with
particular functions or other buttons needed to control the
stimulation and/or drug therapy. Processor 64 may present the
voiding log via the display of user interface 62 and the clinician
may review the voiding log of voiding information to determine an
effective treatment or adjust therapy parameters for the currently
selected therapy.
[0117] Processor 64 may include a microprocessor, microcontroller,
DSP, ASIC, FPGA, discrete logic circuitry, or a combination of such
components. Processor 64 controls user interface 62, retrieves data
from memory 68 and stores data, such as voiding information, within
memory 68. Processor 64 also controls the transmission of data
through telemetry module 66 to IMD 12. Specifically, processor 64
controls receiving voiding information from automatic voiding diary
device 14 and transmission of therapy programs to therapy delivery
device 30.
[0118] Processor 64 may receive parameter set selections made by
patient 10 or a clinician via user interface 62, and may either
transmit the selection or the selected parameter set to IMD 12 via
telemetry module 60 for delivery of drug therapy and electrical
stimulation according to the selected parameter set. Telemetry
module 66 includes a transceiver for wireless communication,
appropriate ports for wired communication or communication via
removable electrical media, or appropriate drives for communication
via removable magnetic or optical media. Telemetry module 60 may
support both wireless communication with IMD 12 and wireless
communication with another programmer or external device.
[0119] In some embodiments, external device 60 may include
input/output module 63 in addition telemetry module 66.
Input/output module 63 allows processor 64 to communicate with
another programmer. For example, where external device 60 stores
parameter sets in memory 68, processor 64 may receive parameter
sets from another programmer via input/output module 63 during
programming by a clinician.
[0120] Memory 68 may include any combination of volatile,
non-volatile, removable, magnetic, optical, or solid state media,
such as ROM, RAM, EEPROM, flash memory, or the like. Memory 68
includes operation instructions for processor 64 and voiding
information. In embodiments, where therapy is also delivered,
memory 68 may also store therapy parameters to define the therapy.
Memory 68 may also include a history of all user inputs and changes
to the voiding information for later review if necessary. In
addition, memory 68 may store voiding information received from
automatic voiding diary 14 (FIG. 2).
[0121] Telemetry module 66 allows the transfer of data to and from
IMD 12. Telemetry circuit 66 may receive voiding information
automatically from automatic voiding diary device 14 as voiding
events are detected, at a scheduled time, when memory within IMD 12
is full, or when requested by a clinician through user interface
62. Power source 69 may be a rechargeable battery, such as a
lithium ion or nickel metal hydride battery. Other rechargeable or
conventional, nonrechargeable batteries may also be used. In some
cases, clinician programmer 18 may be powered by a connection to an
alternating current outlet.
[0122] FIG. 4 is a schematic diagram illustrating a system 80
including a therapy delivery device 82 that delivers therapy to
patient 10 for treating urinary incontinence and an implantable
automatic voiding diary 84. As shown in FIG. 4, therapy delivery
device 82 and automatic voiding diary device 84 are separate IMDs
that wirelessly communicate with one another. Alternatively,
therapy delivery device 82 and implantable automatic voiding diary
84 may be coupled via a wired connection (e.g., a conductor
electrically coupling therapy delivery device 82 to implantable
automatic voiding diary 84). With respect to FIG. 4, therapy
delivery device 82 and automatic voiding diary 84 are substantially
similar to therapy delivery device 30 and automatic voiding diary
14, respectively, of FIG. 1. Consequently, system 80 operates in
substantially the same manner as system 2 shown in FIG. 1.
[0123] In one embodiment, automatic voiding diary 84 includes a
microphone (not shown) that generates an electrical signal based on
a sound associated with a voiding event and a memory that stores
voiding information for detected voiding events. Therefore, it
should be understood that automatic voiding diary 84 generally
operates in similar fashion as automatic voiding diary 14 in FIGS.
2 and 3. For this reason, the details of operation of device 84 are
not described in detail to avoid redundancy in this disclosure.
[0124] In the illustrated example of FIG. 4, therapy delivery
device 82 may be implemented as an INS, drug pump, or other therapy
delivery device well known in the field of IMDs for delivering
stimulation therapy, drug therapy, or a combination of both.
Additionally, similar to therapy elements 15, therapy element 85 is
coupled to therapy delivery device 82 and may represent a lead
carrying one or more electrodes that delivery stimulation in the
form of electrical pulses or a fluid delivery device, such as a
catheter, that delivers one or more drugs. Although only one
therapy element for therapy delivery device 82 is illustrated in
FIG. 4, in some embodiments, therapy delivery device 82 may include
more than one therapy element 85. For example, in some embodiments,
system 80 may include more than one lead that each carry electrodes
for delivering stimulation therapy, more than one catheter that
each deliver one or more drugs, or any combination thereof.
Additionally, therapy element 85 may, in some embodiments, carry
electrodes and deliver drugs for treating urinary incontinence.
[0125] With respect automatic voiding diary device 84, however,
device 84 may be configured to have a capsule-like shape. That is,
the housing of device 84 may have the shape of a rounded capsule
and may have a length of approximately 2 centimeter (cm) to
approximately 5 cm, a width of approximately 1.5 cm to
approximately 5 cm, and a thickness of approximately 0.5 cm to
approximately 2.5 cm. Alternatively, the capsule-like shape may
exhibit a circular cross-section, in which device 84 may have a
diameter of approximately 0.5 cm to approximately 1.5 cm, rather
than width and height dimensions. The shape and size of device 84
may facilitate implantation at locations within patient 10 that
promote sensing of sounds associated with a voiding event.
Accordingly, in an example embodiment, voiding diary device 84 may
be configured to be percutaneously introduced into patient 10. In
such an embodiment, the size and shape of voiding diary device 84
enables it to be introduced using an introducer device, such as a
needle.
[0126] Although not shown in FIG. 4, the microphone used by
automatic voiding diary device 84 may be located on or within the
housing of device 84. Alternatively, the microphone may be carried
on a lead (not shown) that extends from the housing of device 84.
The microphone may be located medially along the length of the lead
or may be located at the distal end of the lead. As previously
described, positioning the microphone at the distal end of the lead
may enable the microphone to be implanted at a particular site
within patient 10 that results in an improved quality of signal
generated by the microphone.
[0127] In any case, automatic voiding diary device 84 operates as a
wireless sensor that is configured to transmit voiding information
to therapy delivery device 82 in addition to or instead of
transmitting voiding information to patient and clinician
programmers 16 and 18. For example, therapy delivery device 82 may
control or adjust therapy parameters based on voiding information
received from automatic voiding diary device 84. In another
example, although not explicitly shown in FIG. 4, automatic voiding
diary device 14 may wirelessly transmit voiding information to
patient and clinician programmers 16 and 18 for diagnostic
purposes. That is, a patient or clinician may use programmers 16
and 18 to view voiding information received from automatic voiding
diary as previously described. Thus, automatic voiding diary 14 may
be implanted within patient 10 to generate voiding information for
the purposes of patient diagnosis both alone or in combination with
therapy delivery device 82.
[0128] System 80 may exhibit certain advantages. For example,
therapy delivery device 82 and automatic voiding diary 84 may be
implanted at different locations within patient 10. For example,
therapy delivery device 82 may be implanted in a subcutaneous
pocket in the lower back or abdomen of patient 10 whereas automatic
voiding diary device 84 may be implanted proximate to bladder 20,
urinary tract 22, or other location proximate to the urinary system
of patient 10. Alternatively, therapy delivery device 82 may be
implanted in a subcutaneous pocket in the lower back or abdomen of
patient 10 whereas automatic voiding diary device 84 may be
implanted proximate to a portion of the intestines, rectum, or
other location proximate to the gastrointestinal tract of patient
10. Implanting automatic voiding diary device 84 at a location
proximate to bladder 20, as shown in FIG. 4, may increase the
likelihood and reliability of detecting a voiding event based on
the electrical signal generated by the microphone of device 84.
That is, by implanting device 84 at a location different than that
of device 82, the electrical signal generated by the microphone of
device 84 may have improved quality. In other words, the electrical
signal generated by the microphone may be closer to the source of
the sounds associated with a voiding event and, at the same time,
exposed to a lesser amount of unwanted noise.
[0129] FIG. 5 is a block diagram illustrating various components of
automatic voiding diary 84. In the illustrated example of FIG. 5,
device 84 includes sensing circuitry 90, sensor 92, processor 90,
telemetry module 96, memory 98, clock 112, and power source 114.
Sensing circuitry 90, sensor 92, processor 94, telemetry module 96,
memory 98, and clock 112 are substantially similar to sensor 42,
sensing circuitry 40, processor 44, telemetry module 36, memory 46,
and clock 48, respectively.
[0130] Accordingly, sensor 42 may be a microphone, such as a
crystal microphone, condenser microphone, a ribbon microphone, or
other type of microphone suitable for implantation within patient
10 that generates an electrical signal based on a sound associated
with a voiding event, as previously described. Sensing circuitry 90
generally processes this electrical signal to detect voiding events
and memory 98 stores the voiding information under the control of
processor 94. Processor 94 may also generate timestamps,
information that identifies detected voiding events as voluntary or
involuntary events, and other information associated with detected
voiding events. As previously described, processor 94 may generate
a timestamp based on a clock signal received from clock 112.
[0131] In response to detecting a voiding event, processor 94 may
store in memory 98 the raw output of sensor 92, the processed
signal that is produced by sensing circuitry 90, or data that
simply indicates that a voiding event was detected. In addition,
processor 94 may also associate and store a timestamp with the
voiding information stored in memory 98 based on a clock signal
received from clock 112. Further, processor 94 may also store as
part of the voiding information associated with a detected voiding
event, data that identifies the detected event as a controlled or
involuntary event. In this case, processor 94 may generate this
data based on a signal received from input mechanism 110. Processor
94 and memory 98 may implement loop recorder functionality or may
be configured to transmit voiding information to device 82 or an
external device, such as patient or clinician programmers 16 and
18.
[0132] Telemetry module 96 may transmit voiding information to an
external device in accordance with wireless telemetry protocols,
Bluetooth, IEEE 802.11 (a), (b), (g), or other standard proprietary
wireless protocols. Telemetry module 96 may also receive
information from an external device. For example, telemetry module
96 may receive updated signal models or templates to use for
detecting a voiding signature in the signal output by sensor
92.
[0133] FIG. 6 is a schematic diagram illustrating a system 120 that
includes therapy delivery device 82 and patient programmer and
automatic voiding diary 124, which is referred to hereafter as
device 124. In general, system 120 operates in a similar fashion as
systems 2 and 80 in FIGS. 1 and 4, respectively, but provides an
automatic voiding diary as an external device instead of a device
implanted within patient 10. In particular, therapy delivery device
82 in FIG. 6 corresponds to therapy delivery device 82 illustrated
in FIG. 4 and delivers therapy to patient 10 for urinary or fecal
incontinence. Device 124, however, is configured to operate similar
to patient programmer 16 and include the functionality of automatic
voiding diary 14 and 84. That is, device 124 operates as an
automatic voiding diary as well as a patient programmer as
previously described in this disclosure.
[0134] Device 124 includes a microphone that may be positioned on
or within the housing of device 124. Since device 124 is an
external device, patient 10 may carry device 124 throughout the
course of a day. Microphone incorporated in device 124 is
positioned external to patient 10, and thus, may be unlikely to
detect or generate an electrical signal indicative of internal
sounds associated with a voiding event, such as sounds produced by
bladder 20, urinary tract 22, rectum (not shown), intestines (not
shown), or other organs and tissue (not shown) that produce a sound
associated with a urinary or fecal voiding event. However, the
microphone incorporated within device 124 may pick up, i.e.,
generate an electrical signal based on, external sounds associated
with a voiding event. These sounds may include but are not limited
to a sound produced by urine or feces being voided into a toilet, a
toilet flushing, fluid exiting urinary tract 22, fluid or feces
being voided into an undergarment, a voice command, or other sound
produced by patient 10 or the environment that is associated with a
urinary or fecal voiding event.
[0135] Device 124 may have the shape and size of a personal
electronic device. For example, device 124 may be described as a
handheld electronic device that is sized to be held in one hand and
can easily be carried in the pocket of a user. Device 124 may or
may not include a LCD screen for displaying a user interface with
which the user can interact to view voiding information or perform
limited programming functions, such as adjust therapy parameters
within a pre-defined range of values. Generally, the size of device
124 may not be substantially larger than the size or patient
programmer 16. This is because few components are needed to add the
functionality provided by automatic voiding diary device 14, i.e.,
to add the functionality of an automatic voiding diary.
[0136] Generally, patient 10 carries device 124 throughout the day.
However, unlike patient programmer 16, it may be particularly
important to carry device 124 close to the body of patient 10. This
is because the distance between device 124 and, more particularly,
the microphone carried by device 124, and the body of patient 10
may affect the performance, i.e., the ability of device 124 to
detect voiding events. For this reason, it may be advantageous to
attach device 124 to the clothing of patient 10 or directly to
patient 10 to reduce the distance between the source of the sound
and the microphone. This may also minimize the possibility of
patient 10 forgetting device 124 at home or at other places, and
decreases any burden to patient 10 to carry patient programmer and
automatic voiding diary device 124.
[0137] In order to increase the likelihood of reliably detecting
sounds associated with a voiding event, device 124 may include
elements for attaching patient programmer and automatic voiding
diary 124 to the clothing of patient 10. Example elements may
include clips, pins, bands, adhesives such as tape or Velcro, and
the like. As an example, device 124 may include a clip, pin, or
band for attaching device 124 to the waist band of pants or
shorts.
[0138] As shown in FIG. 6, patient programmer and automatic voiding
diary 124 wirelessly communicates with clinician programmer 18 and
therapy delivery device 82. Accordingly, patient programmer and
automatic voiding diary 124 includes the communication features
previously described with respect to patient programmer 16 and
device 14. For example, device 124 may transmit voiding information
to clinician programmer 18 for review by a clinician. Therapy
delivery device 82 may also receive voiding information from device
124 for adjusting therapy parameters.
[0139] In this way, device 124 automatically tracks voiding events
and can be used by patient 10 to review voiding information or
provide other input, such as input indicating a voiding event was
voluntary or involuntary. Automatically recording voiding events
eliminates the need for patient 10 to manually track voiding
events, e.g., by entering events in a written or electronic diary.
In embodiments in which patient 10 uses device 124 to review
voiding information, device 124 includes a display, such as an LCD
screen, for presenting the voiding information to patient 10 as a
voiding diary. Patient 10 may also be able to confirm that an event
was detected correctly prior to the event being written to the
diary. Device 124 may also enables patient 10 to enter additional
information associated with the voiding event. As an example,
patient 10 may interact with device 124, e.g., by depressing one or
more buttons, selecting an item from a menu, or the like, to
identify a voiding event as a controlled or involuntary event.
Thus, device 124 combines the operational features of patient
programmer 16 and automatic voiding diary 14 without substantially
increasing the size of patient programmer 16.
[0140] It should be understood that the operational features of
automatic voiding diary 14 and 84 may also be implemented in
handheld electronic devices other than a patient programmer. For
example, a personal digital assistant (PDA), cell phone, watch, or
personal electronic device may be configured to operate as an
automatic voiding diary. In such examples, however, patient 10 may
also carry a patient programmer, although the automatic voiding
diary may be useful without a patient programmer.
[0141] FIG. 7 is a block diagram illustrating various components of
device 124. As described with respect to FIG. 6, device 124
combines the operational features of patient programmer 16 and an
automatic voiding diary, such as automatic voiding diary 14 or 84.
Accordingly, device 124 includes similar components to patient
programmer 16 and device 14.
[0142] In the illustrated example of FIG. 7, patient programmer 124
includes sensing circuitry 130, sensor 132, processor 134,
telemetry module 136, memory 138, clock 142, power source 144, user
interface 146, and input/output module 147. With respect to FIG. 5,
sensor 132, sensing circuitry 130, processor 134, telemetry module
136, memory 138, clock 142, and power source 144 correspond to
sensor 92, sensing circuitry 90, processor 94, telemetry module 96,
memory 98, clock 112, and power source 114, respectively. In
addition, processor 134, telemetry module 136, memory 138, and user
interface 146 and input/output 147 correspond to processor 64,
telemetry module 66, memory 68, user interface 62 and input/output
module 63 of FIG. 3, respectively.
[0143] FIG. 8 is a conceptual diagram illustrating a system 170
including an external device 174 configured to operate as an
automatic voiding diary. In FIG. 8, device 174 may generally be
configured to be easily carried or worn by patient 10. For example,
device 174 may be attached to or otherwise carried by a belt 172 as
shown in FIG. 8. Thus, device 174 may have a reduced size that
facilitates the discrete attachment to the body or clothing of
patient 10.
[0144] Similar to the previously described automatic voiding diary
devices, device 174 includes a microphone (not shown) that
generates an electrical signal based on sounds associated with
voiding events. The microphone may be positioned on or within the
housing of device 174. Device 174 generally does not include
features, such as an interface, for displaying voiding information
to patient 10 or receiving input from patient 10. Rather, device
174 wirelessly transmits recorded voiding information to one or
both of patient and clinician programmers 16 and 18. Accordingly,
device 174 may be viewed as providing similar operational features
as automatic voiding diary devices 14 and 84.
[0145] However, in contrast to devices 14 and 84, device 174 is not
implanted within the body of patient 10. Consequently, device 174
may be particularly useful for patients that are not good
candidates for implantable medical devices. Device 174 may also be
useful as a preliminary diagnostic device to determine if a patient
would benefit from an implantable automatic voiding diary device
and/or implantable therapy delivery device. Furthermore, device 174
may also be useful during a trialing period (or a "calibration
mode") in which external sounds associated with voiding, or voiding
characteristics of the electrical signal generated by the
microphone within device 174 are determined. The external sounds
may differ, depending on the life style of patient 10, and
different patients may generate different external sounds or be
subjected to different environmental sounds during voiding events.
Accordingly, device 174 may be used to "train" the processor within
device 174 or another computing device to recognize certain sounds
or electrical signals as indicative of a voiding event.
[0146] It is important that device 174 be attached to the body or
clothing of patient 10 to increase the likelihood of reliably
detecting sounds associated with a voiding event. For this reason,
device 174 may include elements for attaching device 124 to the
clothing or body of patient 10. As examples, device 174 may include
a clip, pin, or band for attaching device 174 to the waist band of
pants or shorts. As another example, device 174 may include a strip
of Velcro that attaches to a corresponding strip of Velcro on an
undergarment. In this example, the Velcro may be strategically
positioned, e.g., near the groin region of patient 10. In this way,
device 174 may be more likely to detect sounds associated with a
voiding event.
[0147] Placement of device 174 near an undergarment may be
particularly advantageous for detecting involuntary events in which
fluid is voided into the undergarment. That is, the sound of fluid
being voided into an undergarment may be difficult to detect with
an external or internal device because of the reduced volume of
sound in comparison to other sounds (such as the sound produced by
flushing a toilet), and accordingly, positioning the microphone to
the source of the sound may increase the possibility of the
microphone capturing sounds of fluid being voided into an
undergarment. By attaching device 174 to the undergarment at a
location proximate to the opening of the urethra of patient 10, the
distance between the source of the sound and device 174 is reduced.
Additionally, device 174 may also be able to detect other noises,
such as sounds produced by fluid being voided into a toilet or the
sound produced by a toilet flushing, at this location.
[0148] FIG. 9 is a block diagram illustrating various components of
device 174. In the illustrated example of FIG. 9 device 174
includes sensing circuitry 180, sensor 182, processor 184,
telemetry module 186, memory 188, clock 192, and power source 194.
These components are substantially similar to sensor 92, sensing
circuitry 90, processor 90, telemetry module 96, memory 98, clock
112, and power source 114, respectively, of automatic voiding diary
84 of FIG. 5.
[0149] FIG. 10 is a flow diagram illustrating an example technique
for automatically detecting voiding events via a microphone, and
recording voiding information for the detected voiding events. The
example technique may be employed by any of previously described
devices 14, 84, 124 and 174. Although various devices have been
described in this disclosure for generating a voiding diary, FIG.
10 will be described with respect to automatic voiding diary device
14. It should be understood, however, that the flow diagram of FIG.
10 may also be used to describe the operation of other automatic
voiding diary devices that generate a signal indicative of a sound
associated with a voiding event, such as devices 84, 124, and
174.
[0150] The technique begins with device 14 and, more particularly,
the microphone associated with device 14 generating an electrical
signal based on sounds associated with voiding events (190). As
previously described, a sound associated with a voiding event may
be an internal or external noise that can be translated into an
electrical signal by a microphone. Internal sounds may includes
sounds produced by bladder 20, urinary tract 22, rectum (not
shown), intestines (not shown), or other organs and tissue (not
shown) of patient 10 that produce a sound associated with a urinary
or fecal voiding event. External sounds may be sounds produced by
patient 10 or the environment during a voiding event, such as a
sound produced by urine or feces being voided into a toilet, a
toilet flushing, fluid exiting urinary tract 22, urine or feces
being voided into an undergarment, a voice command, or other sound
associated with a urinary or fecal voiding event.
[0151] Generally, device 14 generates an electrical signal
substantially continuously. Thus, only portions of the electrical
signal generated by sensor 92 include a voiding signature. For this
reason, device 14 processes the electrical signal to detect a
voiding event (192). As previously described, processing the signal
may involve comparing the signal to a signal template stored in
memory. Processing the signal may further involve processing the
signal to remove unwanted signal components and utilizing low power
detection techniques, as previously described.
[0152] In some embodiments, device 14 does not generate the
electrical signal substantially continuously, but may enter a sleep
state in which device 14 does not generate the signal if an
amplitude the signal remains below a threshold value for a
threshold amount of time, thus indicating that patient 10 is
sleeping or otherwise not likely to void. The sleep state may help
conserve energy. During the sleep state, device 14 may only
generate the signal periodically, such as about every second, about
every minute, or about every hour. Device 14 may be "awoken" from
the sleep state and enter an active state upon detecting a sound
(via the electrical signal) that is above an awake threshold. The
sleep thresholds and awake thresholds may be determined by a
clinician or a manufacturer of device 14. Alternatively, device 14
may include an accelerometer or another device configured to detect
patient movement, where the accelerometer generates a signal which
causes device 14 to "wake up" from the sleep state. The
accelerometer may generate the "awaken" signal in response to
detecting motion during the night hours or detecting motion after
extended periods of time of inactivity.
[0153] In some cases, device 14 may be used to detect voiding
events during a sleep state (e.g., to diagnose nocturia). In such
cases, the clinician may program device 14 to not enter the sleep
state.
[0154] After processing the signal, device 14 determines if a
voiding event has been detected (194). In the event that a voiding
event has not been detected ("NO" branch of decision block 194),
device 14 generates a signal based on detected sounds (190) and
processes the signals to detect a voiding event (192). In this way,
steps 190, 192, and 194 form a loop that executes until a voiding
event is detected ("YES" branch of decision block 194).
[0155] In response to detecting a voiding event, device 14 stores
voiding information (196). The voiding information may include a
portion of the electrical signal that includes a voiding signature,
data that indicates a detected voiding event, a timestamp
associated with a detected voiding event, and data that identifies
the voiding event as a voluntary or involuntary event. The voiding
information may be stored in local memory or transmitted to an
external device, such as patient or clinician programmers 16 and
18, to be stored. After recording the voiding information in memory
46 (FIG. 2), device 14 may continue generating the electrical
signal based on detected sounds (190), and so forth.
[0156] The voiding information stored within memory 46 may be
displayed to the patient or a clinician via programmers 16 and 18,
respectively (198). The patient may review the information to
verify that the information is correct. A clinician may review the
information to monitor and diagnose a condition of the patient and
to adjust therapy parameters.
[0157] FIG. 11 is a flow diagram illustrating an example technique
for calibrating an automatic voiding diary to detect voiding
events. Similar to the flow diagram illustrated in FIG. 10, the
example technique in FIG. 11 is described with respect to automatic
voiding diary 14 (device 14), but may be employed by any of the
previously described devices including a microphone for generating
a signal indicative of detected sounds, i.e., devices 84, 124, and
174.
[0158] In particular, FIG. 11 shows a calibration mode 200 and an
operational mode 210. In the calibration mode, a sensor signal,
i.e., an electrical signal generated by the microphone associated
with device 14, is monitored (202). The sensor signal is monitored
in a controlled environment. For example, patient 10 may be given
fluids to drink for a period of time to induce a natural voiding
event. Alternatively, a clinician may actively fill the bladder via
a catheter to induce or simulate an actual voiding event.
[0159] As yet another alternative, if device 14 is configured to
generate a signal indicative of external sounds, the calibration
mode 200 in which device 14 "learns" which sounds are associated
with voiding events may be conducted outside of the clinician's
office. As previously discussed, the external sounds associated
with voiding events may differ based on the patient.
[0160] As the sensor signal is monitored, patient 10 provides input
when the voiding event occurs (204). When input is not received,
steps 202 and 204 are repeated, i.e., the process continues to
monitor the received sensor signal for received patient or
clinician input.
[0161] When input is received ("YES" branch of decision block 204),
device 14 defines a voiding signature based on the electrical
signal (206). Defining the voiding signature may involve storing a
waveform of that particular portion of the electrical signal in
memory (208) as a voiding signature template for correlation with
subsequently received signals to identify voiding events. The
voiding signature may include one or more characteristics of the
sensor signal, such as amplitude, frequency, time intervals,
morphology, or the like.
[0162] Upon defining the voiding signature, device 14 may be used
in an operational mode 210 to detecting voiding events. For
example, in one embodiment, device 14 monitors the sensor signal
received from the microphone (212) of device 14 and compares the
sensor signal to the stored signal template to determine whether
there is a substantial signal template match (214). If there is not
a match, the sensor signal continues to be monitored. If a signal
template match is detected ("YES" branch of decision block 214),
however, device 14 records voiding information (216) and, in some
embodiments, takes a specified action (218). The specified action
may be, for example, transmitting the voiding information to an
external programmer or adjusting therapy parameters based on the
voiding information.
[0163] FIG. 12 is a conceptual cross-sectional view of an abdominal
region 204 of a patient, such as patient 10. Abdominal region 204
includes epidermis 206 and subcutaneous tissue 208. FIG. 12 further
shows a device 212 implanted within subcutaneous tissue 208. In
general, device 212 may operate similar to previously described
automatic voiding diary devices 14 and 84, but includes additional
features for providing a user friendly and accurate implantable
automatic voiding diary device. Alternatively, device 212 may
detect urinary or fecal voiding events using other techniques known
in the art. For example, device 212 may detect urinary voiding
events using one or more pressure sensors, flow sensors, strain
gauges, sensing electrodes, or other types of sensors used for
detecting urinary voiding events and detect fecal voiding events
using one or more pressure sensors, strain gauges, sensing
electrodes, such as electromyography sensors for detecting detrusor
or bowel muscle contraction, or other types of sensors used for
detecting fecal voiding events. In any case, when device 212
detects a voiding event or receives a signal from another device
that detects voiding events, device 212 records voiding information
in response to receiving a patient defined action. The voiding
information may be information that identifies a detected voiding
event as a voluntary or involuntary event. In FIG. 12, the patient
defined action is the "tapping" of finger 202 on skin 218 located
above or superior to device 212.
[0164] Because device 212 operates similar to the previously
described automatic voiding diary devices, these common features
are not described in detail with respect to FIG. 12. Rather, the
purpose of FIG. 12 is to describe the additional features of device
212. Unlike the previously described automatic voiding diary
devices, device 212 includes an input mechanism that generates an
electrical signal based on the patient defined action, i.e.,
tapping. This signal is processed and associated with a detected
voiding event (e.g., detected via a microphone within device 212)
to generate data that identifies a detected voiding event as a
voluntary or involuntary event. This data is also referred to as
"identification information" in this disclosure and may be stored
in memory of device 212, or an external device, as part of the
voiding information that forms the voiding diary.
[0165] Identification information may be useful for diagnosing the
condition of patient 10 and determining the efficacy of therapy
that is delivered to the patient. For example, determining the
number of incontinence events and/or the ratio of incontinence
events to involuntary events may be critical to accurately diagnose
the patient and determine the efficacy of therapy. In addition, the
identification information may be used in a closed-loop therapy
adjustment system to adjust one or more therapy parameters. For
example, if the identification information identifies an
involuntary voiding attempt, the one or more therapy parameters may
be adjusted accordingly to better control the patient's urinary or
fecal incontinence.
[0166] The input mechanism that generates the electrical signal
based on the patient defined action may be, for example, a multiple
or single axis accelerometer or a strain gauge that produces a
detectable change in electrical resistance based on the extent of
deformation of the strain gauge, although other input mechanisms
may be possible. For example, in some embodiments, a microphone may
be used to detect the patient defined action, such as the tapping.
The microphone may be similar to the microphone described above
with respect to FIG. 2. The tapping of finger 202 on skin 218
refers to the motion of patient 10 pressing finger 202 downward
into skin 218 located above or superior to device 212 and
subsequently releasing finger 202 from skin 218, as indicated by
the arrows in FIG. 12. Tapping skin 218 in this manner causes
epidermis 206 and subcutaneous tissue 208 to compress and/or
deflect in the direction of motion. This causes device 212 to be
displaced from original location 204A to temporary location 204B
for a period of time before returning to original location 204A.
Original location 204A is indicated in FIG. 12 by the solid outline
of device 212 while the temporary location 204B is indicated in
FIG. 12 by the dashed outline of device 212'. When finger 202 is
released from skin 218, epidermis 206 and subcutaneous tissue 208
return to their normal state and device 212 returns to its original
location 204A. The distance device 212 travels along the axis of
motion is represented by distance 210 in FIG. 12. The distance of
this motion is labeled 210 in FIG. 12. Distance 210 may be
approximately 1 millimeter (mm) to approximately 20 mm or on the
order of approximately 1 mm. Accordingly, the accelerometer may be
positioned on or within the housing of device 212 and may be
capable of detecting movement of the device on the order of
approximately 1 mm to approximately 20 mm.
[0167] Using a single axis accelerometer as the input mechanism for
device 212 may provide certain advantages. For example, since a
single axis accelerometer translates motion along a single axis
into an electrical signal, it may be less likely to misconstrue
other motions as tapping. In other words, the single axis
accelerometer generates an electrical signal based on motion along
a single axis. Therefore, motion along any other axis is not
translated into an electrical signal. As a result, it is less
likely that other patient motions that result in motion of device
212, such as jumping, sitting, standing, and the like, will be
misinterpreted as input, i.e., tapping or other motions for
identifying a voiding event as a controlled or involuntary event.
Further, a single axis accelerometer may provide a less complex and
more power efficient implementation than would otherwise be
possible with a multiple axis accelerometer.
[0168] In operation, one or more taps may be used to identify a
voiding event as a controlled or involuntary event. Each tap may
also be referred to as an input event in this disclosure. In one
example embodiment, a single tap may indicate that a voiding event
was a involuntary event and two or more taps may indicate that a
voiding event was an involuntary or incontinence event. In other
embodiments, any two tapping patterns could be used to identify an
involuntary voiding event from a voluntary event.
[0169] In other example embodiments, other characteristics of one
or more input events may be used to identify a voiding event as a
controlled or involuntary event. Other example characteristics
include the duration of an input event, frequency of input events,
pattern of input events, and the like. The duration of an input
event is defined in this disclosure as the duration of time for
which device 212 is displaced to temporary position 204B (indicated
as device 212' in FIG. 12). In other words, the duration of the
input event may be viewed as the period of time that the patient
presses finger 202 into skin 218. For example, when device 212
detects that it was displaced to temporary position 204B for a
threshold amount of time or greater, device 212 may record voiding
information that indicates a voiding event was involuntary. On the
other hand, when device 212 detects that it was displaced to
temporary position 204B, but for less than a threshold amount of
time, device 212 may record voiding information that indicates a
voiding event was voluntary. In this way, an input event with a
first predefined duration may be used to identify a controlled
voiding event and an input event with a second predefined duration
longer than the first predefined duration may be used to identify
an involuntary voiding event. As an example, the first predefined
duration may be within a range of approximately 1 second or less
and the second predefined duration may be within a range of
approximately greater than approximately 1 second and less than
approximately 3 seconds. Other time durations may be used. In this
way, a single input event can be used to identify a voiding event
as a controlled or involuntary event.
[0170] Alternatively, instead of using the duration of an input
event to identify the nature of a voiding event, the duration of an
input event may be used to increase the reliability of detecting
input events. In such cases the duration of an input event may be
used to distinguish an input event from other motions that may be
misconstrued as a characteristic input provided by the patient. In
other words, since other motions of the patient, such as
scratching, fastening a seat belt, and the like, may mimic the
tapping input with respect to pressing skin 218 for a period of
time, requiring an input event to have a defined duration may limit
false positives.
[0171] In order to distinguish a characteristic "tap" from other
movements that may be misconstrued as a characteristic input, the
"tap" may involve pressing at location 212 for a period of time. By
pressing for a characteristic period of time, this input may be
distinguished from other actions that may be misconstrued as
characteristic input. This may, for example, be useful for
distinguishing displacement caused by sitting and standing. Sitting
and standing may displace device 212 in the same way a
characteristic patient input, but displaces device 212 for an
extended period of time. In other words, a characteristic input
displaces device 212 from its current position to a temporary
position for a relatively short period of time, followed by
returning to the original position. In contrast, sitting down may
displace device 212 from its original position to a second
position. Device 212 may, however, remain in this second position
for a relatively extended period of time in comparison to the
characteristic input. Again, the duration device 212 remains in the
temporary position 204B may be compared to a threshold time period
stored within a memory of device 212 in order to determine whether
an input was intended to be an input.
[0172] The frequency of input events may be used to identify the
nature of a voiding event by using different frequencies to
distinguish between a controlled and an involuntary event. The
frequency is defined as the time between two or more successive
taps or input events. Therefore, a involuntary event may be
identified by two or more taps characterized by a first frequency
and an involuntary event may be identified by two or more taps
characterized by a second frequency greater than the first
frequency. For example, a involuntary event may be identified by
two taps separated by a period of time of approximately half a
second or less. In contrast, an involuntary event may be identified
by two taps separated by a period of time of approximately a second
or more. In this case, the involuntary event may be viewed as being
similar to a "double click" of a mouse. In this way, multiple taps
are required to provide input. Using multiple taps to identify the
nature of a voiding event may be beneficial because it may prevent
device 212 from misconstruing other motions as characteristic input
provided by the patient.
[0173] In other example embodiments, a pattern of input events may
be used to identify a voiding event as a controlled or involuntary
event. In such embodiments, a pattern of input events may be
defined as the temporal relationship between more than two input
events. For example, a pattern may include three input events. In
this case, one example pattern may be characterized by a short time
period between the first and second input events and a longer time
period between the second and third input events. Another example
pattern may be characterized by a long time period between the
first and second input events and a shorter time period between the
second and third input events. A patterned input event may also be
utilized to differentiate between intentional data entry, i.e., a
patient defined action, and device movement resulting from normal
patient actions, such as sitting and other patient actions that may
otherwise be misconstrued as intentional data entry.
[0174] Device 212 may operate in an initial learning or calibration
mode that trains patient 10 to enter the patient defined actions.
For example, in a clinical setting device 212 may be programmed to
enter the learning mode. In the learning mode, device 212 may
expect certain patient defined actions and provide an indication if
the patient defined actions were correctly detected. As an example,
patient 10 may enter a specified patient defined action, such as a
patterned input event that corresponds to identifying a voiding
event as a voluntary event. Upon receiving the input event, device
212 may provide an audible alert or transmit data to an external
monitoring device, such as a patient or clinician programmer, that
prompts patient 10 whether the input was received correctly or
incorrectly. Patient 10 may enter the input event several times in
order to learn or become accustomed to the temporal and pressure
characteristics of the input event that are required for proper
detection by device 212. In other words, patient 10 can repeatedly
enter an input event until the patient has learned to enter the
input event correctly. This training mode may be important for
patient 10 to easily and reliably provide input to identify the
nature of voiding events.
[0175] In addition, the lack of input may be used to identify the
nature of an event in some example embodiments. For example, a
single tap may indicate that a voiding event was controlled and
lack of an input may indicate the event was involuntary. In other
examples, lack of input may be used to reduce the number of false
positives. A false positive occurs when device 212 falsely detects
that a voiding event occurred. In the event that a voiding event is
detected, device 212 may be configured to expect an input from the
patient. The input may be entered within a time frame following the
detection of an event. This time frame may allow sufficient time
for the patient to get to a restroom following an involuntary event
so that the patient may deal with the involuntary event and enter
input in privacy. However, if the patient does not provide input
within the time frame, then the event is identified as a false
positive.
[0176] This may be advantageous because it limits the motions that
may be misconstrued by device 212 as characteristic input. That is,
since device 212 expects input a short time period after detecting
a voiding event, other motions that may normally be
indistinguishable from characteristic input are not registered
because they do not occur during the time window of interest. For
example, following a detected voiding event, device 212 may examine
the signal generated by the accelerometer over a window of time.
This window may be less than approximately five seconds, less than
approximately 10 seconds, or less than approximately a minute. In
any case, it is unlikely that other motions that could be
misconstrued as a patient input will occur during this time window
thereby further increasing the confidence in the signal generated
by the accelerometer within device 212. In the case that patient 10
is aware of a an involuntary voiding event, the lack of input may
be used to identify the event as an involuntary event.
Alternatively, the event may simply not be identified as a
controlled or involuntary event to avoid confusion with the case
that patient 10 forgot to enter input.
[0177] In some embodiments, device 212 may also provide an audible
or other patient detectable alert as a reminder to the patient to
enter input. As one example, device 212 may provide a beep or other
sound that can be heard by patient 10 after a voiding event is
detected. This beep may serve as a reminder to patient 10 to
provide input to identify the voiding event. Alternatively, or in
addition to beeping, device 212 may vibrate in a way that can be
detected by the patient. In this manner, device 212 may reduce the
likelihood that patient 10 forgets to provide input to identify the
nature of a voiding event and, therefore, may reduce false
positives.
[0178] It is recognized that the location at which device 212 is
implanted may have a significant impact on performance of the
device. For example, the performance of device 212 with respect to
detecting a voiding event may be dependent on the proximity of the
implant site to the source of the sound that is used to detect a
voiding event. At the same time, the performance of device 212 with
respect to identifying a voiding event as a controlled or
involuntary event may be dependent on the on the depth at which
device 212 is implanted within subcutaneous tissue 208. In other
words, implanting device 212 in close proximity to the bladder or
urinary tract of the patient and shallow in subcutaneous tissue
208, i.e., just under epidermis 206, may increase the accuracy and
reliability of device 212 of detecting voiding events and
identifying voiding events based on input received from the
patient.
[0179] It should be understood that the embodiment described with
respect to FIG. 12 is one of various example embodiments that may
be used to identify the nature of a voiding event based on a
patient defined action. In other example embodiments, the
microphone may be used to detect a voiding event and receive input
from the patient to identify the nature of the voiding event. In
such an example, tapping skin 212 may produce a noise that is
detected by the microphone. The sound produced by the tapping is
translated into data by the microphone. Accordingly, a device in
accordance with this embodiment may utilize two different signal
processing techniques. A first technique may be used to detect a
voiding event. This technique may be employed substantially
continuously. Upon detecting a voiding event however, a second
processing technique may be used. This second processing technique
may be configured to detect the sound produced by tapping skin
212.
[0180] Identifying a voiding event as a controlled or involuntary
event based on input received from the patient as described in this
disclosure may provide certain advantages. One advantage is that
the automatic voiding diary may be more accurate than a written or
electronic voiding diary in which the patient manually enters data.
In particular, device 212 may include features, e.g., alert
features, which remind the patient to enter data in response to
detecting a voiding event. This may reduce the likelihood that the
patient forgets to enter input and, thus, result in a more complete
voiding diary.
[0181] In some embodiments, voiding information generated by device
212 may be used to automatically adjust therapy parameters based on
the input received from the patient, and in particular, upon
detecting an involuntary voiding event by associating a voiding
event with patient input indicating the event was involuntary.
Device 212 may include a therapy module or may be coupled
(wirelessly or via conductors) to a therapy delivery device. In
embodiments in which device 212 is coupled to a therapy delivery
device, a processor within device 212 may transmit a signal to the
therapy delivery device indicating a request for a therapy
parameter adjustment. Alternatively, the processor within device
212 may merely transmit the therapy information to the therapy
delivery device, which may then process the information to
determine whether to adjust therapy and if so, the adjustments to
the therapy parameters. Therapy parameters may be adjusted to
increase the intensity of therapy in response to detecting an
involuntary voiding event. In this way, the therapy may be
increased, for example by increasing stimulation current amplitude
or stimulation voltage amplitude, until the patient no longer
experiences involuntary voiding events or manually adjusts the
parameters because the therapy is uncomfortable.
[0182] FIG. 13 is a block diagram illustrating various components
of device 212. In the illustrated example of FIG. 13 device 212
includes sensing circuitry 220, sensor 222, processor 224,
telemetry module 26, memory 228, input mechanism 230, clock 232,
and power source 234, which are substantially similar to sensing
circuitry 90, sensor 92, processor 90, telemetry module 96, memory
98, clock 112, and power source 114, respectively, of device 84 of
FIG. 5. Thus, device 212 operates in a similar fashion as automatic
voiding diary 84, but includes the additional features described in
FIG. 12.
[0183] In general, input mechanism 230 generates an electrical
signal in response to patient defined input, such as tapping as
described in FIG. 12. As previously described, input mechanism 230
may be a single or multiple axis accelerometer located on or within
the housing of device 212. Processor 224 processes the output of
input mechanism 230 to generate identification information and
stores the identification information in memory 228. Processor 224
may also control telemetry circuitry 226 to wirelessly transmit the
identification information, as well as other voiding information,
to an external device, such as patient and clinician programmer 16
and 18, respectively.
[0184] FIG. 14 is a flow diagram illustrating an example technique
utilized by device 212 for identifying a voiding event as a
voluntary or involuntary event based on a patient defined action.
The flow diagram begins with device 212 generating an electrical
signal based on a parameter associated with a voiding event (280).
For example, the parameter may be a sound that is associated with
voiding events or a physiological parameter associated with
voiding, such as bladder pressure. In this case, device 212
includes a microphone as previously described in this disclosure.
However, other parameters may also be used to detect voiding
events. As an example, device 212 may include pressure sensors,
flow sensors, strain gauges, wetness sensors, or other sensors that
generate electrical signals that can be used to detect voiding
events.
[0185] In any case, device 212 processes the electrical signal to
detect a voiding event (282). Processing the electrical signal may,
for example, involve comparing the electrical signal to a signal
template stored in memory as previously described in this
disclosure or comparing an amplitude of the electrical signal to a
threshold value. Device 212 continues to monitor the electrical
signal generated by the microphone or other sensor when a voiding
event is not detected ("NO" branch of decision block 284). However,
upon detecting a voiding event ("YES" branch of decision block
284), device 212 monitors the output of the accelerometer to
receive a patient defined action (286).
[0186] As previously described, device 212 may monitor the output
of the accelerometer for a pre-determined window of time following
the detection of a voiding event. If device 212 has not received a
patient defined action within the window of time ("NO" branch of
decision block 286), device 212 generates data that identifies the
detected voiding event as a false positive (294). The false
positive data may be stored within memory (290). In other
embodiments, device 212 may generate data that simply indicates
that the patient did not enter input. In any case, the
identification data (or "identification information") is stored in
memory (290) and may be displayed to a user for review (292).
[0187] When device 212 receives a patient defined action within the
time window ("YES" branch of decision block 286), a processor
within device 212 may associate the input from the patient via the
patient defined action with a voiding event, and generate data that
identifies the event as one of a voluntary and an involuntary event
based on the received patient defined action (288). Device 212 may
then store the identification data (or "identification
information") in memory (290). The identification data may be a
value, flag, or signal that is stored or transmitted to whether a
detected voiding event was controlled (i.e., voluntary) or
involuntary. In some embodiments, voiding information, including
the identification information or data, is displayed to a user for
review (292). In order to display the voiding information to a
user, such as a patient or clinician, device 212 may wirelessly
transmit the voiding information to an external device, such as a
patient or clinician programmer, or another computing device. In
other embodiments, device 212 may merely associate the receipt of
the patient input via the patient-defined action with a voiding
event, and the information may be transmitted to another computing
device to determine whether the input indicates the voiding event
was voluntary or involuntary.
[0188] As previously described, in other embodiments, a patient
defined action confirming that a detected voiding event was in fact
a voiding event may be obtained through techniques other than
device 212. For example, the patient may provide feedback via a
patient programmer or another external computing device, such as by
responding to a prompt from the patient programmer or depressing a
button dedicated to such confirmation input.
[0189] FIG. 15A is a schematic diagram illustrating an automatic
urinary voiding diary system 300. System 300 includes IMD 302
coupled to implantable medical lead 304. Lead 304 has an elongated
body that extends between a distal end carrying sensor 310 and a
proximal end coupled to IMD 302. In general, IMD 302 is configured
to operate as an automatic voiding diary that detects urinary
voiding events based on a sensor signal received via lead 304 and
records voiding information for detected urinary voiding events. In
some embodiments, IMD 302 may also be configured to operate as
therapy delivery device, such as an electrical stimulator, drug
pump, or both. In embodiments in which IMD 302 delivers therapy to
the patient, lead 304 may be configured as a combination lead,
i.e., a lead that includes sensor 310 and therapy element. For
example, lead 304 may include both sensor 310 and electrical
stimulation electrodes, or one or more additional leads may be
coupled to IMD 302, e.g., to deliver electrical stimulation, drug
therapy, or both.
[0190] Although lead 304 is illustrated in FIG. 15A as carrying a
single sensor, i.e., sensor 310, in other embodiments, lead 304 may
carry multiple sensors. The sensors may include one or more
microphones, pressure sensors, flow sensors, strain gauges, sensing
electrodes, temperature sensors, any other type of sensor used for
generating a signal indicative of a parameter associated with
voiding events, or any combination thereof. Lead 304 may carry two
or more different types of sensors. IMD 302 receives an electrical
signal generated by sensor 310 (and any other sensors carried by
lead 304) and processes the electrical signal to detect urinary
voiding events, and records the voiding events in a voiding
diary.
[0191] In the embodiment shown in FIG. 15A, lead 304 is positioned
so that its distal end and, more particularly, sensor 310 is
proximate to bladder 20. However, it should be understood that lead
304 may be implanted at other target sensing sites suitable for
sensing parameters associated with urinary voiding events.
Accordingly, the location of lead 304 within patient 10 may depend
on the type of sensor 310.
[0192] IMD 302 processes the electrical signal generated by sensor
310 to detect voiding events. In particular, IMD 302 may operate as
previously described in this disclosure. For example, sensor 310
may be viewed as the microphone that generates an electrical signal
based on sounds associated with voiding events. Accordingly, IMD
302 may process the sensor signal to detect voiding events using
the previously described signal processing techniques, such as
filtering techniques for removing unwanted signal components,
correlation or comparison techniques that utilize a signal
template, and low power techniques that combine a sleep or low
power state and one of the previously described techniques for
detecting voiding events.
[0193] System 300 may be particularly advantageous in embodiments
in which system 300 is configured to deliver therapy to patient 10
to treat urinary incontinence. Delivering electrical stimulation to
the S3 sacral nerve may help treat urinary incontinence. In such
embodiments, lead 304 may be configured to also deliver electrical
stimulation, drug therapy, or both, at target stimulation site 318
proximate to the S3 sacral nerve. Lead 304 may include one or more
stimulation electrodes (not shown) or have one or more openings
(not shown) for delivering drug therapy. The stimulation electrodes
and/or openings for delivering drug therapy may be located on lead
304 such that when 304 is fully implanted in patient 10 as shown in
FIG. 15A, sensor 310 is positioned proximate to bladder 20 and the
stimulation electrodes and/or openings are proximate to target
stimulation site 318. In this case, the trauma experienced by the
patient during implantation of system 300 is reduced because only a
single lead is required to be implanted to achieve both sensing of
voiding events and therapy delivery to treat incontinence.
[0194] In embodiments in which lead 304 only carries sensor 310 and
a separate lead is used to deliver therapy, certain advantages may
still be achieved. In particular, because lead 304 carries sensor
310 proximate to its distal end, lead 304 may be implanted without
requiring an additional incision. For example, the lead or leads
that deliver therapy may be implanted within patient 10 through an
incision and positioned at a target stimulation site, such as
target stimulation site 318 proximate to the S3 sacral nerve. When
the therapy leads have been implanted, lead 304 may be implanted
through the same incision and positioned at a different target
site. That is, lead 304 is introduced into the S3 sacral foramen
312 of sacrum 314 in the same way that the therapy leads are
introduced. However, lead 304 may be advanced towards bladder 20
and positioned so that sensor 310 is proximate to bladder 20 as
shown in FIG. 15A. Thus, no additional incisions are required and
the trauma experienced by patient 10 is reduced.
[0195] As shown in FIG. 15A, system 300 also may include a
clinician programmer 18 and a patient programmer 16. Clinician and
patient programmers 18 and 16 may be handheld computing devices
that enable a clinician and patient 10, respectively, to view
voiding information and control delivery of therapy. For example,
using clinician programmer 18, the clinician may specify electrical
stimulation or drug therapy parameters.
[0196] Clinician programmer 18 supports telemetry (e.g., radio
frequency telemetry) with IMD 302 to upload electrical stimulation
parameters and, optionally, download operational or physiological
data stored by electrical stimulator 12. In this manner, the
clinician may periodically interrogate IMD 302 to evaluate efficacy
and, if necessary, modify the stimulation parameters. Patient 10
may use patient programmer 16 to start, stop or adjust therapy. In
particular, patient programmer 16 may permit patient 10 to adjust
stimulation parameters such as duration, amplitude, pulse width and
pulse rate, within an adjustment range specified by the clinician
via clinician programmer 18, or select from a library of stored
stimulation therapy programs. Patient and clinician programmers 16
and 18 communicate via cables or a wireless communication, as shown
in FIG. 15A. For example, clinician programmer 18 and patient
programmer 16 may communicate with each other and IMD 302 using any
of a variety of local wireless communication techniques, such as RF
communication according to the 802.11 or Bluetooth specification
sets, infrared communication, e.g., according to the IrDA standard,
or other standard or proprietary telemetry protocols.
[0197] In FIG. 15B, system 300 is configured to operate as a fecal
voiding diary system in which lead 304 is positioned to proximate
to intestines 330. Positioning lead 304 and, more particularly,
sensor 310 proximate to intestines 330 instead of bladder 20
enables lead 304 to be used for detecting fecal voiding events
instead of urinary voiding events. Thus, system 300 in FIG. 15B
operates as described with respect to FIG. 15A.
[0198] The purpose of FIG. 15B is to describe the unique features
of detecting fecal voiding events. These unique features relate to
the positioning of lead 304 and the type of sensor used for sensor
310. Sensor 310 may be a microphone, strain gauge, electromyography
(EMG) sensor, accelerometer, piezoelectric sensor, or other sensor
that generates an electrical signal based on a sound, pressure,
motion, or turbulence caused by the movement of fecal matter in the
intestines, rectum, or bowel during a voiding event. Lead 304 may
be positioned, for example, such that sensor 310 is located
proximate to a portion of the bowel, large intestines, proximate to
the sacrum (e.g., below the sacrum), anus, rectum, descending
colon, or sigmoid colon.
[0199] As an example, lead 304 may be implanted so that sensor 310
is implanted proximate to a portion of the sigmoid colon as shown
in FIG. 15B. In FIG. 15B, rectum 336, sigmoid colon 332, and
descending colon 338 are shown. Specifically, sigmoid colon 332 and
rectum 336 are depicted such that their positions relative to one
another form a "valve" or "fold" that prevents fecal matter from
entering rectum 336. During a fecal voiding event, however, sigmoid
colon 332 and rectum 336 may shift from the illustrated positions
to positions that open the valve or fold thereby allowing fecal
matter in sigmoid colon 332 to pass to rectum 336 and exit anus
334. In the illustrated example of FIG. 15B, sensor 310 generates
an electrical signal based on the motion of sigmoid colon 332 and
rectum 336 relative to the bulk of patient 10. In this case, sensor
310 may comprise one or more strain gauges or accelerometers
disposed along a distal portion of lead 304.
[0200] It should be understood that although FIGS. 15A and 15B
depict a single lead, more than one lead may be used to detect
urinary and fecal voiding events, respectively. Rather, the purpose
of FIGS. 15A and 15B are to illustrate one example embodiment of
the invention and should not be considered limiting of the
invention as broadly described in this disclosure.
[0201] FIG. 16 is a detailed perspective view illustrating an
embodiment of lead 304, which includes lead body 340 extending
between proximal end 342 and distal end 344, sensor 310 positioned
proximate to distal end 344, fixation elements 346A-D (collectively
referred to as "fixation elements 346"), and stimulation electrodes
348A-D (collectively referred to as "stimulation electrodes 348").
Stimulation electrodes 348 are electrically coupled to a therapy
module within IMD 302 via conductors disposed within lead 304. In
particular, lead 304 may include a set of proximal electrical
contacts at proximal end 342 which couple to IMD 302 directly or
indirectly via a lead extension. In some embodiments, electrodes
348 are coupled to separate conductors, which allows separate
stimulation signals to be delivered to each electrode 348. In other
embodiments, two or more electrodes 348 may be coupled to a common
conductor.
[0202] Lead 304 is illustrated in FIG. 16 with a single sensor 310.
However, in other embodiments, more than one sensor maybe located
proximate to distal end 344 of lead 304. As previously described
with respect to FIG. 15A, sensor 310 may be any sensor that
generates an electrical signal based on a parameter associated with
a voiding event, such as a microphone, a pressure sensor, a flow
sensor, a strain gauge, and the like.
[0203] In FIG. 16, electrodes 348 are positioned adjacent to sensor
310 at distal end 344, but may generally be located anywhere along
lead body 340. Positioning electrodes 348 proximate to sensor 310
may be advantageous when the target stimulation and sensing site
are in close proximity to each other. In other embodiments in which
target stimulation and sensing site are in close proximity to each
other, sensor 310 may be located between one or more of electrodes
348. Alternatively, in embodiments that have multiple sensors
located at distal end 344, electrodes 348 and the sensors may be
interspersed with each. For example, electrodes 348 and the sensors
may be arranged in an alternating fashion.
[0204] In other embodiments, electrodes 348 may be disposed on a
medially located portion of lead body 340 between distal end 344
and proximal end 342, rather than proximate to distal end 344 of
lead 304. This may be advantageous when lead 304 is implanted such
that sensor 310 is located proximate to a target sensing site, such
as the bladder or intestines of the patient, and electrodes are
located proximate to a remotely located target stimulation site
relative to the target sensing site, such as the S3 sacral nerve.
In additional embodiments, electrodes 348 may be disposed proximate
to proximal end 342 of lead body 340.
[0205] Fixation elements 346 may help fix lead 304 to surrounding
tissue and minimize migration of sensor 310 and electrodes 348 from
their respective target sensing and stimulation sites. Fixation
elements 346 may be located adjacent to both sensor 310 and
electrodes 348 or, alternatively, fixation elements 346 may only be
located proximate to one of sensor 310 and electrodes 348. In
embodiments in which sensor 310 is located at distal end 344 and
electrodes 348 are located at a different position along lead body
340, fixation elements may preferably be located adjacent to both
sensor 310 and electrodes 348. Moreover, it may be advantageous for
fixation elements to be located both proximally and distally
relative to sensor 310 and electrodes 348. In this manner, fixation
elements 346 may prevent sensor 310 and electrodes from migrating
and, therefore, prevent a degradation in the performance of lead
304.
[0206] Fixation elements 346 may be, for example, tines, barbs,
hooks, and so forth. Alternatively, lead 304 may be sutured to
surrounding tissue in order to secure the position of sensor 310
and electrodes 348. Suturing, however, is typically more invasive
then fixation elements 346. In some cases, fixation elements 346 or
suturing lead 304 to surrounding tissue may not be beneficial at
all implantation sites. Therefore, it should be understood that
fixation elements 346 depicted in FIG. 16 are merely exemplary and
the number and location of fixation elements 346 may be changed
based on the implant site of lead 304.
[0207] An example of a lead including a sensor configured to
generate a signal that varies as a function of a parameter
associated with a voiding event, and thus, may be used to determine
whether a voiding event occurred, is described in commonly-assigned
U.S. patent application Ser. No. ______ by Martin T. Gerber et al.,
entitled, "IMPLANTABLE MEDICAL LEAD INCLUDING VOIDING EVENT
SENSOR," (attorney docket number 1023-668US01/P0029148.00) and
filed on the same date as the present disclosure, the entire
content of which is incorporated herein by reference.
[0208] FIG. 17 is a block diagram illustrating various components
of IMD 302 and lead 304 of system 300. IMD 302 is an implantable
automatic voiding diary that includes lead 304 with a sensor 310
disposed at distal end 344. As shown in FIG. 17, IMD 302 includes
sensing circuitry 352, processor 354, telemetry module 356, memory
358, and therapy delivery module 360. IMD 302 is substantially
similar to IMD 12, which is shown and described with respect to
FIG. 2. Thus, the description of sensor 42, sensing circuitry 40,
telemetry module 46, and therapy delivery module 32 are
substantially applicable to a description of sensor 310, sensing
circuitry 352, telemetry module 356, and therapy delivery module
360, respectively. Similarly, processor 354 and memory 358 of IMD
302 are substantially similar to processor 44 and memory 46,
respectively, of IMD 12.
[0209] FIG. 18 is a flow diagram illustrating an embodiment of a
technique for implanting IMD 302 and lead 304 including a distal
sensor 310 and stimulation electrodes 348 in the body of patient
10. In particular, the technique may be used to implant lead 304 by
introducing lead 304 through a foramen of the sacrum. A clinician
may make an incision in the abdomen (370) or other suitable area of
the patient, such as the lower back or buttocks, where the incision
is sized to receive IMD 302. Next, the clinician implants IMD 302
in a subcutaneous pocket (372) through the incision. The clinician
may form the subcutaneous pocket in any region of patient 10, such
as the abdomen. The location of the incision (370) may depend upon
the desired implant site for IMD 302. Accordingly, in other
embodiments, the incision and subcutaneous pocket may be made in
other regions, such as the lower back of patient 10.
[0210] Upon implanting IMD 302, the clinician makes another
incision near the sacrum (374) and inserts lead 304, as well as any
additional leads, through this incision (376). Next, the clinician
positions the leads (378), i.e., lead 304 and any additional leads,
by introducing the leads through a foramen of the sacrum and
guiding lead 304 to target stimulation site 318 (FIGS. 15A-B). As
an example, the clinician may position lead 304 through sacral
foramen 312 in sacrum 314 in order to reach target stimulation site
318 and the target sensing site, as shown in FIGS. 15A and 15B. The
clinician may fine-tune the position of lead 304, such that sensor
310 is proximate to a portion of bladder 20 for sensing urinary
voiding events or a portion of the intestines 330 for sensing fecal
voiding events. In embodiments in which lead 304 also carries
stimulation electrodes, the stimulation electrodes may be
positioned proximate to target stimulation site 318, e.g., the S3
sacral nerve. In embodiments in which the clinician implants
multiple leads within patient 10, the clinician may insert and
position each of the leads separately. In some embodiments, the
multiple leads may be inserted through a single incision thereby
minimizing the trauma experienced by the patient.
[0211] After properly positioning lead 304 or multiple leads within
patient 10 (378), the clinician may tunnel a proximal end 342 of
lead 304 to IMD 302, and couple the proximal end 342 to IMD 302
(380). The clinician may then activate IMD 302 and proceed to
monitor the condition of the patient via an external programmer and
begin delivering or testing therapy as needed.
[0212] Various embodiments of the invention have been described.
These and other embodiments are within the scope of the following
claims.
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